Assessing the Global Climate in August 2018

The global land and ocean temperature departure from average for August 2018 was the fifth highest for the month of August in the NOAA global temperature dataset record, which dates back to 1880. The June to August global temperature was also the fifth warmest such period on record, while the year-to-date was fourth warmest on record.

This monthly summary, developed by scientists at NOAA's 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.

August 2018 Temperature

• The August temperature across global land and ocean surfaces was 1.33°F above the 20th century average of 60.1°F and the fifth highest for August in the 1880-2018 record. Nine of the 10 warmest August global land and ocean surface temperatures have occurred since 2009, with the last five years (2014-2018) comprising the five warmest on record. The record warmest August occurred in 2016, with a temperature departure from average of +1.62°F. August 1998 is the only 20th century August among the 10 warmest on record, ranking as the seventh highest on record at +1.22°F.

  • August 2018 also marks the 42nd consecutive August and the 404th consecutive month with temperatures, at least nominally, above the 20th century average.

  • Record warm temperatures during the month were present across parts of each major ocean basin, with the largest portions across the Barents Sea and the western Pacific Ocean, and small areas across Africa, Asia and North America. No land or ocean areas had record cold August temperatures.

• The August globally averaged land surface temperature was 1.69°F above the 20th century average of 56.9°F. This value was the sixth highest August land temperature in the 139-year record.

  • The most notable warm land temperature departures from average during August 2018 were present across much of Europe, central Asia, the northeastern contiguous U.S. and southeastern Canada, where temperatures were 3.6°F above average or higher. In contrast, the most notable cool land temperature departures from average were present across northern Canada and parts of southern South America where temperatures were 2.7°F below average or lower.

  • Warmer-than-average temperatures were present across much of Europe during August 2018, giving way to the warmest August, at 4.32°F, since continental records began in 1910. This value surpassed the previous record set in 2015 by +0.22°F. Several European countries had an August temperature that ranked among the five highest on record.

  • North America had its smallest temperature departure from average for August since 2009. South America and Africa had their smallest August temperature departures from average since 2013.

• The August globally averaged sea surface temperature was 1.21°F above the 20th century monthly average of 61.4°F – also the fifth highest global ocean temperature for August in the record. The years 2014-2018 comprise the five warmest Augusts on record, with 2015 the warmest August at 1.42°F above average.

August 2018 Sea Ice

• The August average Arctic sea ice extent was the seventh smallest in the 40-year record at 614,000 square miles (22.1 percent) below the 1981-2010 average, according to analysis by the National Snow and Ice Data Center using data from NOAA and NASA. This was the largest August Arctic sea ice extent since 2014. The rate of ice loss slowed during August compared to earlier in the summer. Sea ice coverage was below average for most coastal seas of the Arctic Ocean with the Northern Sea Route open by the end of the month. The Northwest Passage continued to be clogged by ice.

• Antarctic sea ice extent during August was 140,000 square miles (2.1 percent) below the 1981-2010 average, the fifth smallest August extent on record. Antarctic sea ice expanded at a rate faster than average during the second half of August. Below-average ice coverage was observed in parts of the northern Weddell Sea and the southern Indian Ocean.

Seasonal (June-August 2018)

• The June-August average temperature across global land and ocean surfaces was 1.33°F above the 20th century average of 60.1°F and the fifth highest for June-August in the 1880-2018 record. This value was 0.29°F cooler than the record high set in 2016 and was the smallest June-August temperature departure from average since 2013.

  • Record warm temperatures during the three-month period were present across parts of the Barents Sea, Europe, southern Asia, western and south-central Pacific Ocean, and scattered across the Atlantic Ocean and North America. No land or ocean areas had record cold temperatures during June-August 2018.

• The globally averaged land surface temperature for June-August was 1.84°F above the 20th century average of 56.9°F. This value was also the fifth highest for June-August in the 139-year record.

  • Four of six continents had a June-August 2018 temperature that ranked among the eight warmest such periods since continental records began in 1910. Of note, Europe had its warmest June-August on record at 3.89°F, surpassing the previous record (2003) by +0.47°F. The seasonal European average for June-August 2018 also marks the first time the continent’s summer temperature was 3.6°F above average or higher in the 109-year record.

• The June-August globally averaged sea surface temperature was 1.15°F above the 20th century average of 61.5°F – tying with 2009 as the fifth highest for June-August in the record.

Year-to-Date (January-August 2018)

• The year-to-date temperature across global land and ocean surfaces was 1.37°F above the 20th century average of 57.3°F – the fourth highest for January-August in the 139-year record. The 2018 year-to-date value was 0.47°F lower than the record high set in 2016.

  • Based on three simple scenarios, 2018 will likely end up among the six warmest years on record.

• The year-to-date globally averaged land surface temperature was 2.09°F above the 20th century average of 49.7°F. This value was also the fourth highest for January-August in the record.

• The year-to-date globally averaged sea surface temperature was 1.10°F above the 20th century average of 61.1°F. This was the fifth highest for January-August in the 1880-2018 record.

For a more complete summary of climate conditions and events, see our August 2018 Global Climate Report.