NOAA's National Centers for Environmental Information
Issued 12 January 2024
Please note that the values presented in this report are based on preliminary data. They will change when the final data are processed, but will not be replaced on these pages.
National Drought Overview
(Very warm and very wet are defined as temperatures or precipitation in the upper tenth percentile of the historical record. Very cold and very dry are defined as temperatures or precipitation in the lowest tenth percentile of the historical record.)
Overall, when integrated across the nation and across the entire year, 2023 was a warm and dry year. The annual nationwide ranks were fifth warmest and 43rd driest), based on data for 1895-2023. But this was a year of extremes as considerable variation occurred throughout the year and across the country. On balance, the year was unusually wet across much of the Northeast, from western portions of the Great Plains to California, and in parts of the Great Lakes and Southeast. The year ended up unusually dry from the Southwest to Gulf of Mexico coast, large parts of the Mississippi Valley, the Ohio Valley to Mid-Atlantic, and parts of the Pacific Northwest, with Louisiana having the eighth driest year on record. Unusually warm temperatures characterized much of the year across much of the contiguous U.S. (CONUS), with 35 states ranking in the top ten warmest category, including Texas, Louisiana, Mississippi, New Hampshire and Massachusetts each having the warmest year in the 1895-2023 record.
Weather conditions varied across the country from month to month during 2023, with short-term very dry conditions and unusual anomalous warmth frequently occurring. Some areas were excessively dry during one part of the year and excessively wet during another part:
- About five percent or more of the contiguous U.S. (CONUS) was very dry during every month except January, February, March, October, and December, with ten percent or more very dry in April (17.1%), July (23.1%), and November (15.0%). Nationwide, July was driest with more than a fifth of the CONUS very dry. Expansive very wet conditions balanced the large dry areas (on a national basis) during July, but the actual amount during July was only 10.1% compared to 23.1%. Five percent or more of the CONUS was very wet during every month except May, September (4.95% before rounding), and November, with ten percent or more very wet during January (23.6%), February (10.1%), March (21.0%), June (12.0%), July (10.1%), August (26.3%), October (10.3%), and December (20.0%). During January to March, more of the country was very wet than very dry, and the wet conditions occurred where it had been dry which helped contract drought. The percent area statistics indicate that a back-and-forth occurred during the middle to last half of the year, with dryness dominating in April, wet conditions balancing the dryness in June, July having dryness dominate again, then August marking a return of wetness, wet and dry percentages relatively low and nearly equal in September, wet dominating in October, dry in November, and wet in December.
- Unusually warm temperatures dominated much of the country during most months. At least five percent of the CONUS was very warm in every month, and at least ten percent was very warm in all months except March and April. About a fourth (25%) or more was very warm in January (39.1%), February (29.5%), May (25.0%), July (49.1%), August (36.6%), September (42.5%), and December (78.8%). Above-normal temperatures enhance evapotranspiration which worsens drought conditions. This was especially a problem during the late spring, summer, and early fall for the Upper Midwest, Deep South, and Pacific Northwest. Only two months had more than five percent of the CONUS very cold — March (18.8%) and June (5.3%).
-
Several areas that were very dry during one part of the year and very wet during another part include:
- the Southwest (Four Corners states) (generally dry during April, July-August, and October; wet during January, March, and May)
- the Pacific Northwest (dry during January-February, July, and parts during May-June and October-December; wet in March-April and parts in August-September)
- California-Nevada (dry April and October-December; wet January, March, June, and August-September)
- the Midwest (dry May-June, September, and November, with parts dry in July-August and December; wet in parts January-March, April, July, October, and December)
- the southern Plains (especially Texas) (dry July-September and in parts January-April, June, and November-December; wet in parts April-May, October, and December)
- New England (dry February and November; wet January, June-September, and December)
The Palmer Z Index incorporates moisture supply (precipitation) and moisture demand (evapotranspiration) to depict the total moisture status each month. The Palmer Z Index maps below show the monthly moisture status for each month in 2023:
On a national scale, large areas of drought affected the country throughout 2023. The year began (January 3) with drought and abnormal dryness in most of the West and Plains, and parts of the Mississippi Valley, Ohio Valley, coastal Southeast, and Hawaii, with moderate to exceptional drought covering about 46.3% of the CONUS (38.7% of the 50 States and Puerto Rico) according to U.S. Drought Monitor (USDM) statistics. The drought area contracted during the first half of the year, reaching a minimum area of 19.0% of the CONUS (15.8% of the 50 States and Puerto Rico) on May 30 as drought contracted in the West, Midwest, Plains, and Southeast. It expanded to reach a maximum extent of 40.1% of the CONUS (33.6% of the 50 States and Puerto Rico) on October 3 with the epicenter expanding from the central Plains to the Upper Midwest, Deep South, and Pacific Northwest. From there the drought area contracted to end the year covering 33.0% of the CONUS (27.6% of the 50 States and Puerto Rico). The areas least often affected by drought included New England, Alaska, parts of the West and Southeast, and most of the U.S.-Affiliated Pacific Islands (USAPI). The areas most often affected by drought included the Pacific Northwest, Southwest, Great Plains, and Upper Midwest, as well as parts of the Mid-Atlantic, Gulf of Mexico coast, Hawaii, and northwest Puerto Rico.
Drought in Hawaii expanded during January 2023 then ended by February, only to return and expand as dry conditions developed during the summer, accompanied by a devastating wildfire on Maui. A record-wet winter and spring brought an end to drought across much of the West — especially in California to the Great Basin — but it lingered throughout the year in the Pacific Northwest and returned to the Southwest (Four Corners states) when the summer monsoon collapsed. Drought continued in the central Plains throughout the year, with the region becoming the epicenter of drought in the CONUS by summer. Precipitation to the north and south during the first half of the year contracted drought in those parts of the Plains. Alternating months of dry and wet conditions expanded then contracted drought in parts of the southern Plains — especially Texas. Dry conditions were accompanied by record heat from the Southwest to central Gulf of Mexico coast during late spring and summer, resulting in rapid expansion of severe flash drought — especially in the Lower Mississippi Valley. A dry spring through fall in the Upper Mississippi and Ohio Valleys brought drought to the Midwest, although parts of the region alternated between wet and dry conditions during the last half of the year. Drought in the Mississippi and Ohio tributaries of the broader Mississippi basin this year, combined with reduced groundwater from three years of drought in the Missouri tributary before this year, resulted in record low levels of the Mississippi River again this year. Soils dried out, ponds and lakes dried up, and crops withered from the Midwest to Deep South. According to the U.S. Department of Agriculture (USDA), the percent of the nation's topsoil moisture short or very short (dry or very dry) peaked at 58% in mid-September, ranking this year behind only 2022 in the recent historical record for dry soils. The percentage of the nation's pasture and rangeland in poor to very poor condition peaked at 40% on October 22. By the end of the year, the USDA had designated 1,866 counties as having drought disaster incidences — about 57.5% of the total number of counties and county-equivalents in the 50 States and U.S. territories. Reduced precipitation during the fall expanded drought into the Tennessee Valley and across the interior Southeast. Dry conditions and drought plagued the Mid-Atlantic region off and on throughout the year. Reduced rainfall in the spring brought a peak in the drought area on Puerto Rico, while dry conditions resulted in drought throughout the year in the U.S. Virgin Islands, with drought conditions there peaking in early fall. As the year ended, drought and abnormal dryness were expanding in the USAPI.
The USDM maps for the end of each month in 2023:
Palmer Drought Index* monthly statistics, which go back to the beginning of the 20th century, indicate that 18.3% of the CONUS was in moderate to extreme drought at the beginning of 2023 (end of January). Like the USDM statistics, the Palmer percentage decreased through the spring, bottoming out at 14.1% at the end of April, then expanded again, reaching a peak of 37.1% at the end of the year.
| Month | USDM CONUS |
USDM all of US |
Palmer CONUS |
Very Dry |
Very Warm |
|---|---|---|---|---|---|
| Jan | 42.7 | 35.7 | 18.3 | 3.4 | 39.1 |
| Feb | 38.5 | 32.1 | 17.2 | 4.1 | 29.5 |
| Mar | 28.2 | 23.6 | 19.8 | 4.2 | 9.5 |
| Apr | 24.4 | 20.4 | 14.1 | 17.1 | 8.6 |
| May | 19.0 | 15.8 | 15.1 | 8.8 | 25.0 |
| Jun | 27.0 | 22.6 | 18.3 | 9.4 | 14.9 |
| Jul | 28.1 | 23.5 | 22.3 | 23.1 | 49.1 |
| Aug | 34.3 | 28.8 | 29.1 | 9.7 | 36.6 |
| Sep | 40.1 | 33.6 | 32.8 | 8.0 | 42.5 |
| Oct | 36.5 | 30.7 | 28.6 | 4.0 | 11.2 |
| Nov | 36.1 | 30.3 | 35.9 | 15.0 | 12.2 |
| Dec | 33.0 | 27.6 | 37.1 | 3.6 | 78.8 |
*This drought statistic is based on the Palmer Drought Index, a widely used measure of drought. The Palmer Drought Index uses numerical values derived from weather and climate data to classify moisture conditions throughout the contiguous United States and includes drought categories on a scale from mild to moderate, severe and extreme.
Regional Drought Overview
West Overview
The West (Rocky Mountains to Pacific Coast) had been suffering from a multi-year drought characterized by years with low precipitation and persistent unusual warmth. Half or more of the last 22 years have been drier than the long-term average, with 2013 ranking as the second driest year regionwide in the 1895-2023 record, 2020 ranking as fourth driest, 2002 seventh driest, 2007 13th driest, and 2009 18th driest. Above-normal precipitation near the end of the year improved 2022's rank to 27th driest. A wet start to 2023 gave this year a rank of 61st wettest (69th driest) regionwide. But 2023 ended on a drier note with mountain snowpack well below normal across most of the West by the end of December.
The West has experienced a general and persistent increasing trend in temperatures for the last 40 years. Nine of the top ten warmest years have occurred since 2003 and 14 of the warmest 20 years have occurred since 2000. These include 2015 (warmest year in the 129-year record), 2014 (third warmest), 2021 (fourth warmest), and 2020 (fifth warmest). The only year in the top ten category that wasn't from the 21st century was 1934 (second warmest). Near- to colder-than-normal temperatures dominated most of the West during the first half of this year, keeping 2023 out of the top 20 warmest category. But excessive heat during the second half of the year gave 2023 a rank of 26th warmest.
The last 24 years across the West, which have been described by some as a "megadrought", have seen frequent episodes of drought briefly interrupted by wetter spells. The three years, 2020-2022, were a period of persistently dry and hot conditions, with the percent area of the region in drought reaching a period-of-record peak — in June 2021 (99.0% of the West) according to the Palmer Drought Index (period of record 1900-2023), and on December 7, 2021 (94.6% of the West) according to the USDM (period of record 2000-2023). In both datasets, the percent area rapidly declined in late 2022 and early 2023, reaching a 2023 minimum of 2.6% in April in the Palmer dataset and a minimum of 14.7% on July 4 in the USDM dataset. The drought area increased again during the last half of the year, ending 2023 at 40.8% in the Palmer dataset and 25.1% in the USDM dataset.
The parts of the West that benefited least from the drought and heat reprieve in 2023 were the Pacific Northwest and the Southwest (Four Corners states).
Pacific Northwest
According to USDM data, the drought area in the Pacific Northwest peaked at about 59.1% of the region early in the year (February 28), then contracted to a minimum of 28.0% on June 6 before increasing again to reach a secondary peak of 52.1% on August 29. Dryness in the Pacific Northwest during 2023 was especially acute along the Oregon and Washington coast during May-July, which ranked as the driest May-July on record for Oregon climate division 1 (Coastal Area) and second driest for Washington climate division 1 (West Olympic Coast). The dry conditions were exacerbated by excessive temperatures, especially during the summer when the Pacific Northwest, as a whole, experienced the third warmest May-August in the 1895-2023 record (tied with 1958).
Southwest
Like the Pacific Northwest, the Southwest U.S. began the year with extensive drought (50.0% of the region in moderate to exceptional drought on January 3, 2023, according to USDM data). The drought area rapidly declined with beneficial precipitation early in the year, reaching a minimum of 7.4% of the region on July 18. But the summer monsoon underperformed this year, being wet one month and dry the next. The cumulative effects of the eleventh driest April regionwide and driest July (tied with 2003), combined with unusually hot temperatures beginning in May, resulted in an increase in the drought area during the summer. The drought area in the Southwest peaked at about 51.7% of the region on November 28, due in part to a record warm July-December.
Great Plains Overview
The Great Plains of the U.S. stretch from Montana and North Dakota to Texas. This large region experienced unusually dry conditions, regionwide, during the previous three years, with 2020 ranking as the 25th driest year in the 129-year record, 2021 the 33rd driest, and 2022 the 13th driest. Above-normal precipitation during 2023, especially in the western sections, improved conditions with 2023 ranking as the 44th wettest year, regionwide, but it was not enough to eliminate the deficits that had built up the previous three years in most areas. Temperatures were unusually hot during all 4 years and have dominated the weather for much of the last 25 years.
The year began with 40.6% of the Great Plains in moderate to extreme drought, based on the Palmer Drought Index, and 2023 ended with 18.8% covered. The drought epicenter stretched from the southern to central Plains at the beginning of the year. Beneficial 2023 rains in parts of the Plains broke up the drought epicenter into three smaller areas in the extreme southern, central, and extreme northern parts by the end of the year.
Northern Plains
Much of the northern Plains was wet for much of 2023. Dry conditions recurred in northern parts of the region, especially in July, August, and November. For the year, northern parts of North Dakota were dry as seen on the 12-month Standardized Precipitation Index (SPI) map, while southern and western parts of the northern Plains were wet. The dryness resulted in drought in these areas on the end-of-year USDM map. Unusually hot temperatures occurred frequently during 2023, especially in May-June, September, and November-December. These resulted in a record hot May-December for much of the region.
Central Plains
Parts to much of the central Plains experienced continued dry conditions in 2023, especially in March-June, September, and November, while beneficial rains fell during other months. Spring was particularly dry, with Kansas having the seventh driest March-April and Nebraska having the sixth driest March-April and fourth driest February-April. Temperatures were unusually warm during the last half of the year, especially during September and November-December. Nebraska had the second warmest September-December and Kansas had the fourth warmest September-December.
Southern Plains
The southern Plains experienced alternating periods of very dry and very wet conditions during 2023, with some parts very wet and other parts very dry during the same month. The year began with 60.9% of the region in moderate to exceptional drought, based on the USDM. The drought area reached a minimum of 33.6% on June 27, then expanded to peak at 78.1% on September 5 before contracting again to end the year at 44.1%.
The summer was particularly dry across a large part of the region. Texas had the fourth driest July-August, statewide, and eighth driest July-September. Extreme heat accompanied the dryness. Texas was record warm for much of the year, with the warmest July-September, May-October, January-September, January-October, January-November, and January-December. The excessive heat has been going on for several years, with the state having the warmest 48-month January-December period on record. In fact, Texas has had a significant warming trend since the late 1970s.
Mississippi River Basin Overview
The Mississippi River experienced the lowest water levels for the second year in a row, closing off a vital channel to barge traffic at a crucial time of the year for transport of crops from the nation's heartland. This resulted from extreme dryness occurring in the Upper Mississippi and Ohio tributaries beginning in late spring this year, in the Tennessee tributary in the fall, in the Lower Mississippi Valley at various times during the year, but especially in the late summer and fall, and in the Missouri tributary during the previous three years. Drought developed rapidly due to the low precipitation and high evapotranspiration that resulted from extremely warm temperatures.
For the Mississippi River and its tributaries, 2023 began with 19.9% of the extended basin in moderate to extreme drought, based on the Palmer Drought Index, and ended with 32.4% in drought. The drought area peaked at 33.2% at the end of November, which is much less than the expansive droughts of the 1930s, 1950s, 1980s, and even the last decade. Basinwide, 2023 ranked as the 43rd driest but seventh warmest year on record. The last two decades have been a period of persistent excessive warmth.
Upper Mississippi Basin
The Upper Mississippi River Basin had the sixth driest May-August and fourth driest November, basinwide, in the 1895-2023 historical record. Record dryness occurred within the basin during May-August. Temperatures were unusually warm to record hot during January, May-June, and September-December. The region had the warmest December and second warmest April-December on record.
Based on the Palmer Drought Index, the Upper Mississippi River Basin began 2023 with 2.6% of the area covered in drought. The drought area rapidly expanded during the summer, peaking at 78.0% by the end of November and ending the year at 56.5%. While extensive, this is less than the peaks of earlier decades. According to USDM data, 2023 began with 31.4% of the basin in moderate to exceptional drought. The drought area shrank to 4.0% of the basin on April 25 before expanding again to peak at 85.9% on July 11. The drought area oscillated up and down after that, ending the year at 51.5%.
Iowa has been the epicenter of drought in the Upper Midwest (Upper Mississippi River Basin) for much of 2023 and beyond. This year (January-December 2023) ranked as the 19th driest year, statewide, in the 129-year record, 2022 was 21st driest, 2021 51st driest, and 2020 35th driest. Collectively, the last two years ranked as the seventh driest such 2-year period and the last four years ranked as the ninth driest such 4-year period. This persistent dryness has kept parts of Iowa in some level of drought (based on the USDM) for the last 183 weeks (since July 7, 2020), which is a record drought duration for the state.
Ohio Basin
Dry conditions occurred over the northern half of the Ohio River Basin during May-June and over most of the basin in September and November-December. The basin had the eleventh driest September, ninth driest November-December, and eighth driest September-December. The year began with record warm temperatures in January-February. Unusual warmth returned near the end of the year, with the Ohio Basin having the seventh warmest September-December.
Based on the Palmer Drought Index, the Ohio River Basin began 2023 with 7.6% of the area covered in drought. Drought ended in the spring, reappeared in the summer, then rapidly expanded during the fall, peaking at 29.1% by the end of December. This is far less than the peaks of earlier decades. According to USDM data, 2023 began with 17.2% of the basin in moderate to exceptional drought. The drought area shrank to zero percent of the basin by February, expanded to 46.4% by June 13, shrank again then expanded again, peaking at 53.5% of the basin at year's end.
Tennessee Basin
The Tennessee River Basin was dry starting in September and going to the end of the year. The basin had the second driest September-December on record. As with the nearby Ohio Basin, for the Tennessee Basin the year began with record warm temperatures in January-February (tied with 2017), and unusual warmth returned near the end of the year, with the Tennessee Basin having the eleventh warmest October-December.
Based on the Palmer Drought Index, the Tennessee River Basin was drought-free in 2023 until late in the year when the drought area rapidly expanded in November to peak at 70.6% of the basin by the end of December. This is less than the peaks of earlier decades which, due to the small size of the basin, reached 100% several times. According to USDM data, 2023 began with no drought in the basin. Drought developed in June and went into a period of expansion and contraction in the summer and early fall. The drought area rapidly grew in October, reaching a peak of 96.6% of the basin on November 21 before contracting slightly to end the year at 90.7%.
Lower Mississippi Basin
The Lower Mississippi River Basin experienced dry conditions off and on during the first half of the year, with dryness becoming persistent during the second half. May-December 2023 was the third driest such 8-month period on record. Unusually hot temperatures plagued the Lower Mississippi every month except April and November. The net effect of the persistently anomalous temperatures was to give the basin the warmest year on record. The record heat increased evapotranspiration which exacerbated the drought conditions that were brought on by the persistent lack of precipitation.
Based on the Palmer Drought Index, the Lower Mississippi River Basin began 2023 drought-free. Drought appeared in March but rapidly expanded in late summer and fall to reach a peak of 70.4% of the basin by the end of December. This is less than the peaks of earlier decades. According to USDM data, 2023 began with very little (2.8%) drought in the basin. Drought expanded in June and steadily grew the rest of the year to peak at 90.1% of the basin at year's end.
Louisiana was especially hit hard by the drought. The state had the driest August and second driest May-November and July-December, as well as several other time periods that ranked second driest. Several time periods ranked record warm, resulting in the warmest year on record and the warmest 18-month May-October period on record. On November 14, Louisiana experienced the greatest coverage of exceptional drought (74.2%) in the 24-year USDM record.
Missouri Basin
The Missouri River Basin, as a whole, experienced a relatively wet year this year, with 2023 ranking as the 41st wettest year on record. But this year followed three very dry years — 2022 ranked as the 19th driest year on record, 2021 was 30th driest, and 2020 the 12th driest, basinwide. Collectively, these three years ranked as the eighth driest such 3-year period on record. When they are combined with 2023, the 2020-2023 4-year period ranks 17 th driest. Very dry conditions covered much of the Missouri Basin during January 2020-December 2022. Even with the above-normal precipitation of 2023, much of the basin still has precipitation deficits for the 4-year period, January 2020-December 2023.
Unusual heat accompanied the dryness. Basinwide, 2023 ranked as the 13th warmest year on record. But when the warmth of the previous three years is included, January 2020-December 2023 ranks as the fifth warmest such 4-year period on record.
Based on the Palmer Drought Index, the Missouri River Basin began 2023 with 28.4% coverage in moderate to extreme drought. The drought area bounced up and down throughout the year, reaching a secondary peak of 26.4% at the end of September and reaching a low value of 16.2% at the end of February. Much more of the basin has been covered in drought in past decades. According to USDM data, 2023 began with 64.5% of the basin covered in moderate to exceptional drought. The drought area steadily declined throughout the year to end at 19.4% at year's end.
Rio Grande River Basin
The Rio Grande River Basin experienced dry periods and wet periods during 2023. The driest period was early summer with June-July ranking as the second driest such 2-month period on record, but the first half of the year was generally dry with February-July ranking as the tenth driest such 6-month period. More notable was the persistent record heat. Some parts of the basin were warmer than normal for almost every month of the year, with late spring to the end of the year seeing the most extreme heat. Every time period from March-December through July-December was record warm, with the year ranking as the fourth warmest January-December.
Based on the Palmer Drought Index, the Rio Grande River Basin began 2023 with 17.9% coverage in moderate to extreme drought. The drought area steadily grew throughout the year, reaching a peak of 100% by the end of October and ending the year with 98.4% coverage. Other years in the 20th and 21st centuries have had 100% of the basin in drought, with the 1950s period being the most persistent. According to USDM data, 2023 began with 25.6% of the basin covered in moderate to exceptional drought. The drought area oscillated up and down throughout the year, reaching a peak of 93.7% on September 5 which persisted until October 3, and ending the year at 82.0%.
Southeast
There were several epicenters of drought in the Southeast that developed at different times of the year. Drought was centered in Florida for the first half of the year, with extreme drought developing in a strip along the west coast. Other parts of the state experienced normal to wet conditions. Unusually hot temperatures occurred in the state during the first half of the year, with Florida having the hottest January-June on record. Hot temperatures also occurred during the second half of the year, giving the state the second warmest year on record.
The hot and dry conditions from the southern Plains and Lower Mississippi Valley spread eastward into western portions of the Southeast as summer progressed, so that drought had developed in the Florida panhandle and southern Alabama by the end of August. Dry conditions intensified across western portions of the Southeast and developed over northern portions during fall, resulting in rapid expansion of drought in these areas. The South Atlantic/Gulf River Basin, which encompasses the Southeast, experienced the 15th driest July-October. The basin also experienced the warmest January-March on record, third warmest July-August, warmest January-August, and second warmest year.
Based on the Palmer Drought Index, the South Atlantic/Gulf River Basin began 2023 with 14.1% coverage in moderate to extreme drought. The drought area oscillated up and down throughout the year, reaching a peak of 38.9% by the end of March and a second peak of 23.7% at the end of November, ending the year with 17.9% coverage. This is considerably less than the droughts of earlier this century. According to USDM data, 2023 began with 20.6% of the Southeast region covered in moderate to exceptional drought. The drought area oscillated up and down throughout the year, reaching a peak of 62.4% on November 21, then rapidly falling to 29.7% by the end of the year.
Mid-Atlantic
Drought developed in the Mid-Atlantic region this year, centered in Maryland and Virginia but especially in Maryland. Dry conditions were particularly acute during January, March, May, August, and October, with wet conditions occasionally occurring in the other months and especially in Virginia. The net effect of the dry months gave Maryland the fifth driest January-May and seventh driest January-October. Anomalously warm temperatures accompanied the dryness, especially in January-April and July-October. Maryland ranked warmest on record for January-April and second warmest for the year.
Hawaii
Hawaii began 2023 with 11.4% of the state in drought. A wetter-than-normal February ended drought across the islands, but drought returned with a vengeance in the summer, covering 60.8% of the state by the end of August. Continued dry conditions expanded the drought area to a peak of 93.6% which occurred from November 7 to November 28, with wet conditions shrinking the drought area to 21.7% by year's end. During the height of this year's dryness, Hilo had the driest June-October and second driest March-December, Kahului recorded the second driest August-October, Honolulu turned in the fourth driest July-September, and Lihue had the fourth driest June-October.
Puerto Rico and U.S. Virgin Islands
The year began with no drought in the U.S. Caribbean islands. A dry spring brought drought, with the drought area peaking at 45.0% of Puerto Rico in moderate drought on April 4. Drought lingered on the island for the rest of the year, contracting into the summer, expanding slightly in the fall, then contracting again, ending the year with 4.8% of Puerto Rico in moderate drought. Precipitation varied across the island, by location and month to month, with San Juan experiencing the eighth driest May-September in the 1956-2023 record. Hot temperatures plagued most of the year, with San Juan recording the warmest year on record; in fact, all of the time periods from January-December through October-December were the warmest on record.
Much of the year was drier than normal and warmer than normal for the U.S. Virgin Islands (USVI). Conditions were worse on St. Thomas and St. Croix than on St. John. Moderate drought developed on St. Thomas and St. Croix in February; St. Croix worsened to severe drought by the end of March and extreme drought in May; St. Thomas was in severe drought by May and extreme drought by July. Exceptional drought developed on both in September. On St. John, moderate drought didn't develop until May; severe drought developed in June, with conditions vacillating between moderate and severe drought through September. Wet weather in October ended drought on St. John and improved conditions to severe drought on St. Thomas and St. Croix. By the end of the year, severe drought continued on St. Thomas but St. Croix had improved to moderate drought.
The weather station at Rohlsen Airport on St. Croix recorded the driest July-September in the 1951-2023 record and (if years with too many missing days are excluded) the driest December-September. They also had the warmest August-November and June-October.
U.S.-Affiliated Pacific Islands
In the U.S.-Affiliated Pacific Islands (USAPI), 2023 began with severe drought affecting Kapingamarangi (in the Federated States of Micronesia) (FSM) while the rest of the USAPI was free of drought and abnormal dryness. By February, drought ended at Kapingamarangi but moderate drought developed in the Marshall Islands (RMI) at Kwajalein and Wotje. Moderate drought briefly returned to Kapingamarangi in March, with Wotje worsening to severe drought. All of the USAPI was free of drought by the end of April, although some areas of abnormal dryness existed. May and June had no drought or abnormal dryness, with drought returning to Wotje and developing on Tutuila in American Samoa in August. The USAPI was once again free of drought by mid-October. But in December, moderate drought returned once again to Wotje and had developed in the western FSM with moderate drought at Yap and severe drought at Ulithi.
Drier-than-normal weather characterized the last half of the year at some locations. Here are selected precipitation ranks for the period:
-
July:
- Kwajalein: second driest July in the period 1949-2023
-
September:
- Ailinglaplap: second driest September (1986-2023)
- Majuro: third driest September (1952-2023)
-
November:
- Pago Pago: second driest November (1966-2023)
- December:
- November-December:
- September-December:
-
July-September:
- Kwajalein: second driest July-September (1949-2023)
- July-December:
- March-December:
