California seeing higher humidity
The normally dry heat of Southern California isn’t so dry this summer. This season’s heat wave over the region is unusual not just for its intensity, but its long duration. It’s even been long enough to raise the water temperatures of the Pacific Ocean just offshore from around Los Angeles down to San Diego, and then on down into Mexico where ocean temps have been unusually warm for the past several years. Typically, the waters off San Diego are in the upper 60s in early August, but this year they’re well up into the 70s, occasionally even flirting with 80 degrees, which would be an all-time high for that location.
Usually humidity levels are famously comfortable in San Diego, but the warmer ocean is sending dew points above 60 degrees, which is considered muggy, to as high as 70 degrees, which is oppressive. This isn’t unique to this heat wave, however. Southern California has been experiencing warmer ocean waters during the summer, along with the higher humidity levels, since at least 2014. This summer, high pressure that usually parks itself over the Four Corners region for weeks on end has taken up residence over California instead.