By Reginald Stanley. Posted August 31, 2026, 11:57 PM.

The recent stretch of exceptionally hot days across Southern California, has been exacerbated by modest humidity and high dew points - a rather uncommon combination for the region.

Widespread high temperatures in the upper 90s and 100s across the inland valleys since roughly August 19, were compounded with unusually high heat index readings (Heat Index being a calculation that translates air temperature readings into what the conditions currently "feel like" to humans). Inland, heat index values exceeding 110 degrees were observed nearly every afternoon over the past week - brought on by unusually warm SSTs (Sea Surface Temperatures) off the Southern California coast, which contributed to relatively high humidity and high dew points during what was already a significant heat wave baking the region during the hottest time of the year. Dew points were unusually high along and near the coasts, frequently in the 70s, compared to more typical dew points in the 40s and 50s. Dew points were not quite as high inland (most of the time), however they were still well above normal. Stepping outside during nighttime did not bring any relief from the daytime heat, as conditions were especially muggy even under clear skies - in addition to nighttime temperatures already significantly warmer the average.

Only the final two days of August was a reprieve from the heat, as the upper ridge regime responsible for our recent unpleasant weather, is displaced by the emergence of an upper level trough across the northeastern Pacific Ocean. Daytime temperatures dropped to between 5 and 10 degrees below average since Sunday. High dew points and humidity will remain for coastal areas, however the region is forecast to see a continuation of the cooling trend in the coming days.