CNN – Hot summers are nothing new for much of the United States, but the combination of heat and humidity has taken on a truly antagonistic role this year, pushing us closer to our melting points in an already uncomfortable season.
Dew point temperatures – a measure of how much moisture is in the air – have soared to sauna-like highs over and over. It’s another way a climate heating up from fossil fuel pollution is changing summer as we know it.
A warm atmosphere soaks up water like a sponge, driving both air and dew point temperatures higher than they’d be in a cooler world.
“Summertime heat that’s being boosted by climate change is now also getting this extra piece,” said Shel Winkley, a meteorologist with the non-profit research group Climate Central. “It’s like a one-two punch.”
For nearly half the country, this summer’s duo of heat and humidity has been record-breaking so far: June through July marked the muggiest start to the season in more than 40 years, based on a CNN analysis.
Here’s what’s behind this summer’s especially soupy start.
Where muggy is topping the charts
The eastern half of the US is typically home to the most muggy, humid conditions in the country, but this summer has been extreme.
Through July, 22 states from the Mississippi Valley to the East Coast have notched their muggiest start to summer since 1981, when the dataset of dew point temperatures used for CNN’s analysis began. It’s been the second-most humid summer for the US as a whole in the same timeframe.
Higher dew points mean there’s more moisture in the air, and when there’s more moisture in the air, it feels more humid.
Dew point temperatures are always the same as or lower than the air temperature …
