Assessing the Global Climate in October 2019

The global land and ocean surface temperature departure from average for October 2019 was the second highest for the month of October in the 140-year NOAA global temperature dataset record, which dates back to 1880. The year-to-date temperature for 2019 was also the second warmest on record for the January–October period. 

This monthly summary, developed by scientists at NOAA National Centers for Environmental Information, is part of the suite of climate services NOAA provides to government, business, academia and the public to support informed decision-making.

October Temperature

• The October temperature across global land and ocean surfaces was 1.76°F above the 20th century average of 57.1°F and the second highest October temperature on record. This value was only 0.11°F shy of tying the record warm October set in 2015.

  • The 10 warmest Octobers have all occurred since 2003; however, the five warmest Octobers have all occurred since 2015.

  • The Octobers in 2015, 2018 and 2019 were the only Octobers with a land and ocean surface temperature departure from average above 1.62°F.

  • October 2019 also marks the 43rd consecutive October and the 418th consecutive month with temperatures, at least nominally, above the 20th century average.

  • The Northern Hemisphere’s October land and ocean surface temperature departure from average of +2.18°F tied with 2015 as the warmest October on record. The Southern Hemisphere land and ocean surface temperature departure from average was the third warmest on record at 1.33°F above average, falling behind 2015 (warmest) and 2018 (second warmest).

  • Record warm October temperatures were mainly present across parts of the North and Western Pacific Ocean and northeastern Canada, as well as scattered across parts of the South Atlantic Ocean, Africa, Europe, the Middle East, the Indian Ocean and South America. Only a small area in the western contiguous U.S. had record cold October temperatures.

• The October globally averaged land surface temperature was also the second highest for October in the 140-year record at 2.63°F above the 20th century average of 48.7°F. Only October 2015 was warmer by 0.05°F.

  • The most notable warm temperature departures from average were observed across much of Alaska, northern Canada, north-central Russia, eastern Europe, the Middle East and western Australia, where temperatures were at least 3.6°F or higher. The most notable cooler-than-average temperatures were present across parts of the western half of the contiguous U.S. and southwestern Canada, where temperatures were at least 2.7°F below average or cooler. 

  • Regionally, Europe, Africa, Asia, Oceania, the Caribbean region, the Gulf of Mexico and the Hawaiian region had an October temperature departure from average that ranked among the top four warmest Octobers on record. Of note, the Hawaiian region had its second warmest October (tied with 2015) on record. 

• The October globally averaged sea surface temperature was 1.44°F above the 20th century monthly average of 60.6°F, the second highest global sea surface temperature for October on record. October 2015 was warmer at +1.57°F. 

Sea Ice and Snow Cover

• The Arctic sea ice extent for October 2019 was the smallest on record at 1.04 million square miles, or 32.22%, below the 1981–2010 average, according to an analysis by the National Snow and Ice Data Center (NSIDC) using data from NOAA and NASA. The October 2019 Arctic sea ice extent surpassed the previous record set in 2012 by 88,800 square miles. The ten smallest October Arctic sea ice extents have occurred since 2007. The NSIDC reported that the daily sea ice extent went from third lowest to the lowest daily extent during October 13–30. On 18 October 2019, the daily sea ice extent was 1.19 million square miles below average — the largest daily departure from average on record. At the end of the month, the daily extent ranked as the second lowest, behind 2016.

• For the fourth consecutive October, the Antarctic sea ice extent was below average. October 2019 Antarctic sea ice extent was 6.89 million square miles, giving way to the 10th smallest October Antarctic sea ice extent on record. This value is 100,000 square miles, or 1.38%, below the 1981–2010 average.

• According to data from NOAA and analyzed by the Rutgers Global Snow Lab, the Northern Hemisphere snow cover extent during October was 1.82 million square miles above the 1981–2010 average and the fifth highest October snow cover extent in the 52-year record. The North American and Eurasian snow cover extents were also above average, ranking as the third and seventh largest snow cover extent, respectively.

Year-to-date (January–October 2019)

• The year-to-date temperature across global land and ocean surfaces was 1.69°F above the 20th century average of 57.4°F — the second highest for January–October in the 140-year record. Only January–October 2016 was warmer at +1.85°F. 

  • The most notable warm temperature departures from average were present across much of Alaska, northwestern Canada and central Russia, where temperatures were at least 3.6°F above average. Meanwhile, the most notable cool temperature departures from average were present across much of the north-central contiguous United States and south-central Canada, where temperatures were at least 1.8°F below average or cooler.

  • Record warm January–October temperatures were observed across much of the southern half of Africa, western Indian Ocean, Madagascar, and across parts of Australia, the western Pacific Ocean, Asia, the Atlantic Ocean and North and South America. No land or ocean areas had record cold temperatures during January–October 2019.

  • The Northern Hemisphere land and ocean surface temperature was the second highest January–October on record at 2.05°F above average. Only January–October of 2016 was warmer (+2.27°F). The Southern Hemisphere's January–October 2019 land and ocean surface temperature was 1.35°F above average –- also the second warmest such period on record, behind 2016 by 0.09°F.

  • Regionally, South America, Europe, Africa, Asia, Oceania and the Hawaiian region had a January–October temperature average that ranked among the three highest such period on record.

• The year-to-date globally averaged land surface temperature was 2.54°F above the 20th century average of 48.7°F. This value was the third highest for January–October on record, behind 2016 (warmest) and 2017 (second warmest). 

• The year-to-date globally averaged sea surface temperature was the second highest for January–October in the 1880–2019 record at 1.39°F above the 20th century average of 61.0°F, only 0.09°F cooler than the record warm January–October set in 2016.

For a more complete summary of climate conditions and events, see our October 2019 Global Climate Report.