The 250th anniversary of our independence will be a warm one, with highs approaching the record of 98° set in 2023. Lingering dry air, though, will keep thunderstorms at bay and heat indices from getting too far out of hand. Still, we can expect heat indices to push into the 100-105° range in the afternoon, so you’ll want to make sure you’re getting plenty of fluids and time in the shade. We’ll have a few clouds from time to time, but otherwise expect plenty of sunshine, especially at the beaches. Make sure you’re applying sunscreen regularly as the UV index is expected to reach 10 during the height of the day. Have a safe and enjoyable holiday!
A hot and increasingly humid airmass will blanket the Lowcountry for the Fourth of July holiday weekend. Temperatures will run in the mid-90s each day, and with dewpoints climbing back into the 70s, heat indices will continue to escalate into the 100s, with the highest values each day being found in the Highway 17 corridor where the best overlap of dewpoints and air temperatures will be found. Heat indices will peak around 100-101° on Friday, 102-106° on Saturday, and should approach the Heat Advisory threshold of 108° on Sunday. Nights will impart increasingly less relief, too, with lows climbing into the upper 70s to around 80° by Sunday, warmest near the coast and in downtown Charleston. The warm nights will compound heat stress, especially for folks who don’t have adequate cooling, which is why it’s so important to take it easy during these hot stretches.
If you’re looking for thunderstorms to cool things off, I wouldn’t really count on those either. The atmosphere should stay capped Friday and Saturday, with a slightly better chance for a stray storm on Sunday but still low enough of a chance as to be technically unmentionable (~10%). If a storm can kick off, watch for frequent lightning and gusty winds. With that being said, the vast majority of us should get a rain-free holiday weekend in.
High pressure continues to dominate the weather pattern, which keeps things toasty and rain-free for Thursday. Fortunately, drier air will still be in place for one more day, which will allow for lows to drop to the low 70s in the morning. From there, we’ll warm to the mid-90s in the afternoon. Dewpoints will mix down to the mid-60s, keeping heat indices within a degree or two of the air temperature. It’ll still be plenty hot, but a drier heat will be appreciated.
High pressure remains the primary weather driver at the surface and aloft for the rest of the work week, keeping temperatures toasty. Northeast flow over the next couple days, though, helps to bring in some drier air, which will keep heat indices from popping off too much. Wednesday starts in the low-to-mid-70s, with temperatures warming into the low to mid-90s in the afternoon under generally partly cloudy skies. The aforementioned stacked high pressure and influx of drier air will keep convection to a minimum.
High pressure wedging southward into the Lowcountry and the resulting northeasterly flow will take a slight edge off the heat for Tuesday after another day in the mid-90s on Monday. It’ll still be a steamy start, though, and the low of 78° will get awfully close to the record warm low temperature of 79° set in 2024. We’ll warm into the low 90s in the afternoon, but dewpoints running in the low to mid-70s will drive the heat index into the upper 90s (standing in contrast to the mid-100s we’ve felt the past few days). High pressure ridging in aloft will put a lid on thunderstorm activity, though some of the convection-allowing models still try to squeeze out a few showers in the afternoon. Rain is highly unlikely, though, so don’t count on it.
