News•June 22, 2015

U.S. Summers Bringing More and More Heat

By Climate Central

It’s officially summer! We have now passed the points that mark the traditional start to summer (Memorial Day), the meteorological start (June 1), and now the astronomical start, or summer solstice (June 21) — so break out those flip-flops and beach towels!

Though June, July, and August usually bring the heat, for parts of the country spring felt decidedly more like summer. Florida had its warmest spring on record and Georgia its third warmest. Seven states in the West had a spring that ranked among the top 10 hottest on record, exacerbating the historic drought there. Even some Northeastern states saw a record-warm May.

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Overall, summer temperatures are heating up across the country, having risen steadily since the 1970s. For the contiguous states over that period, temperatures overall have increased at a rate of about 0.4°F per decade for a total of nearly 2°F since 1970.

But the warming isn’t the same in every region of the country, with some regions and climate divisions (localized areas within regions) seeing their temperatures rise faster than others. The most dramatic warming is evident in parts of the East Coast and the Southwest where temperatures in some of those divisions have risen more than 3°F since 1970.

This ratcheting of blistering summer heat has been fueled by the buildup of heat-trapping greenhouse gases, such as carbon dioxide, in the Earth’s atmosphere because of human activities. According to the recent National Climate Assessment, annual average temperatures in the U.S. could rise another 10°F by century’s end if emissions aren’t abated.

See how summer temperatures in your region stack up by clicking on the map above.