Monthly Report Summary Information

National Summary Information - June 2015

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For extended analysis of regional temperature and precipitation patterns,as well as extreme events, please see our full report that will be released on July 13^th.

Significant climate events for June 2015

June 2015 was 2^nd warmest for the contiguous US

Record warmth engulfed the West; drought worsened in the Northwest; and record precipitation fell in the Ohio Valley.

The June contiguous U.S. average temperature was 71.4°F, 2.9°F above the 20^th century average, second only to June 1933 in the 121-year period of record. Record and near-record warmth stretched from the Rockies to West Coast. The average contiguous U.S. temperature for the first half of 2015 was 49.5°F, 1.9°F above the 20^th century average, and the 10^th warmest January-June on record.

The June precipitation total for the contiguous U.S. was 3.53 inches, 0.60 inch above average. This was the ninth wettest June on record, and marked the third consecutive month of above-average precipitation for the Lower 48. Above-average precipitation was observed in the Southwest, Southern Plains, Ohio Valley, and Northeast; the Northwest was dry.

This analysis of U.S. temperature and precipitation is based on data back to January 1895, resulting in 121 years of data.

June

Temperature

June 2015 Temperature Departure from Average (top)
and Precipitation Departure from Average (bottom)

• Above-average temperatures were widespread in the West and along the Southeast coast, where 16 states were much warmer than average. California, Idaho, Oregon, Utah, and Washington were each record warm for June. Several western cities set new all-time June temperature records during an intense heatwave the second half of the month, including Boise, Idaho where the temperature soared to 110°F.
• The Northeast and Great Lakes region had near- to below-average June temperatures. Above-average precipitation across the region was associated with suppressed daytime temperatures, while nighttime temperatures were near- to above average.
• The Alaska statewide average temperature for June was the sixth warmest in 91-years of record keeping at 52.4°F, 3.1°F above average. Homer, Alaska had its warmest June on record. Prolonged warmth and dryness and lack of June snow created ideal wildfire conditions with dozens of large wildfires impacting central and southern areas of the state during June.

Precipitation

• Wetter than average conditions were widespread from the Southwest, in parts of the Great Plains, and across the Midwest and Northeast — 15 states were much wetter than average. Illinois, Indiana, and Ohio were each record wet during June with monthly precipitation totals more than twice the 20^th century average.
• Below-average precipitation was observed in the Northwest, where drought conditions worsened due to both record warmth and lack of precipitation. Oregon had its ninth driest June, while Washington had its third driest.
• According to the June 30 U.S. Drought Monitor report, 25.9 percent of the contiguous U.S. was in drought, up from 24.6 percent at the beginning of June. Drought conditions improved across the Southwest, Upper Midwest, and the Northeast, but worsened in the Northwest and Southeast. Drought conditions remain dire across California, with 46.7 percent of the state experiencing the worst category of drought (D4, exceptional).

U.S. climate highlights: Year-to-date (January-June)

Temperature

Jan-Jun 2015 Temperature Departure from Average (top)
and Precipitation Departure from Average (bottom)

• Above-average January-June temperatures were observed from the Great Plains to the West Coast, as well as in Florida. California, Nevada, Oregon, and Washington each had their warmest year-to-date on record. Eight additional states were much warmer than average, including Alaska which had its second warmest January-June in the 91-year period of record with a temperature 5.1°F above average. The California year-to-date temperature was 58.5°F, 5.2°F above average, and 0.5°F warmer than the previous record set just last year.
• Below-average year-to-date temperatures were observed across the Midwest and Northeast, where Maine, New York, and Vermont were each much cooler than average. No state was record cold for the six-month period.

Precipitation

• The year-to-date contiguous U.S. precipitation total was 16.53 inches, 1.22 inches above the 20^th century average, the 19^th wettest January-June on record and wettest since 1998.
• Above-average precipitation was observed across the Great Plains, Southern Rockies, and Midwest where four states were much wetter than average. Texas had its wettest year-to-date on record with 24.04 inches, 10.70 inches above average. Below-average precipitation was observed across the West, Southeast, and Northeast. California had its fifth driest start to the year, while Oregon had its ninth driest.

Extremes

• The U.S. Climate Extremes Index (USCEI) for the year-to-date was 45 percent above average and the 13^th highest value on record. On the national-scale, extremes in warm maximum and minimum temperatures and days with precipitation were much above average. The USCEI is an index that tracks extremes (falling in the upper or lower 10 percent of the record) in temperature, precipitation and drought across the contiguous United States.

For extended analysis of regional temperature and precipitation patterns, as well as extreme events, please see our full report that will be released on July 13^th.