Charleston Weather Blog

Forecast explanations, atmospheric science, and other cool weather-related stuff for Charleston, SC

Rest of the work week: Back to the 90s

/ August 12, 2025 at 6:06 PM

90° temperatures have been tough to come by so far this August. (Please note this is not necessarily a complaint.) Since August 1, only today (August 12) has been a 90° day. It’ll get a little easier to achieve the 90° mark going forward, though, as ridging aloft continues to build in. High pressure in the mid-levels helps temperatures heat up while keeping more widespread thunderstorm activity tamped down. We’ll have plenty of humidity in play, which will allow heat indices to head into the low 100s each afternoon — hot for sure, but not Heat Advisory hot, at least. And yes, there will be a chance for a few thunderstorms each day primarily along and ahead of the seabreeze (with perhaps better coverage on Friday). A couple storms could turn strong or even severe where outflow boundaries collide, and heavy rainfall is certainly a concern as well given deep moisture. However, once again, we’ve had much worse very recently, and shouldn’t have a replay of the past weekend for a bit. Just be ready to head indoors in case thunderstorms approach, and you’ll be fine.

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Tuesday: Back to heat

/ August 11, 2025 at 7:45 PM

After a rambunctious Monday that featured widespread showers and thunderstorms leading to flash flooding downtown as well as a lightning strike caught on camera in Mt. Pleasant, the weather will return to a more traditional summertime pattern beginning Tuesday as Charleston County heads back to class. Temperatures will start on the mild side, generally in the mid-to-upper 70s, warming to the upper 80s in the afternoon. Mix in the continued humidity, and it’ll feel closer to 98°. Scattered showers and storms should fire again in the afternoon along and ahead of the seabreeze, and yes, there is a risk of heavy rain with these storms, but the risk for flash flooding will be a bit lower especially as storm motions should be a bit faster.

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