San Antonio is no stranger to hot weather, but as August 2025 draws to a close, the city is facing a particularly stubborn stretch of sweltering temperatures. According to the National Weather Service (NWS), the region is bracing for highs near 99 degrees on Friday, August 29, with heat index values soaring up to 103. Winds will offer little relief, blowing softly from the south at just 5 to 10 mph. As evening falls, the skies are expected to remain mostly clear, and temperatures will dip only slightly, settling near 78 degrees overnight.
Saturday won’t bring much of a respite. The NWS forecast predicts that the mercury will climb even higher, reaching 101 degrees, with heat index values peaking at 105. Again, residents should expect only modest breezes from the south-southeast, and nighttime lows will hover around 78 degrees. For those hoping for an immediate break in the relentless heat, patience is required. The weather pattern, as reported by Hoodline, indicates a stubborn continuity of high temperatures and minimal wind support, keeping the city in a state of near-constant warmth.
Yet, change is on the horizon—albeit a gradual one. Starting Saturday afternoon, there’s a 30 percent chance of showers and thunderstorms after 1 p.m., though the heat will remain oppressive, with highs nearly touching 99 degrees. While this might seem like a modest glimmer of hope, the NWS suggests it could mark the beginning of a shift toward cooler, wetter conditions. Saturday night may see a subtle drop in temperature if the showers materialize, offering some relief to San Antonians who have grown weary of the unyielding sun.
Earlier in the week, North Texas experienced a sharp and sudden cool-down as a late-summer cold front swept through, dropping temperatures nearly 20 degrees below average across the Texoma region. However, as reported by the San Antonio Express-News, that front stalled near the Dallas-Fort Worth area and failed to bring meaningful cooling to the southern half of the state. As a result, San Antonio continued to sizzle, with daily high temperatures averaging 98 degrees throughout the week leading up to August 29.
Looking ahead to the weekend, the forecast models show a new cold front poised to push further south across Texas. While the front is expected to move through the northern half of the state on Friday, it will likely stall out again, this time well north of San Antonio, according to the National Blend of Models. The city will continue to endure above-average heat, with morning temperatures in the mid- to upper 70s quickly climbing to around 90 degrees by late morning and peaking at 100 degrees by mid-afternoon. The chance of rain on Friday remains slim—less than 20 percent—so most locals shouldn’t expect much relief just yet.
Saturday’s outlook is a tale of two regions. The front will likely sit across Central Texas, splitting the state. While much of North Texas enjoys afternoon highs in the mid-80s, South Texas, including San Antonio, will still see temperatures in the upper 90s. There’s about a 20 percent chance of isolated storms near San Antonio, with higher storm chances developing north of the city. The NWS Austin/San Antonio office told MySA that locals should expect highs around 102 to 105 degrees through Saturday, but “don’t fret, a switch in our luck hits over the weekend.”
The real turning point appears to come on Sunday, August 31. As the cold front finally begins to push through, rain chances in South Texas jump to 40-50 percent, and the risk of flooding and strong, damaging winds increases. The Weather Prediction Center at the National Weather Service has placed all of Central and South Texas under a level one out of four risk, or at least a 5 percent chance, of excessive rainfall. While not everyone will see significant rainfall, several storms may be capable of producing locally heavy downpours and gusty winds up to 50 mph. “Rounds of scattered showers and strongest storms capable of producing locally heavy downpours,” the NWS Austin/San Antonio office posted on X. “While the flooding threat is not widespread, this heavy rain could lead to isolated instances of flash flooding.”
Overnight Sunday into Monday, the chances for precipitation remain elevated, with a 40 percent chance of rain Sunday night. Labor Day, Monday, September 1, is expected to bring even more change. Forecast models have higher confidence that temperatures will decrease to below-average levels, with San Antonio likely seeing highs in the upper 80s to low 90s and overnight lows in the low to mid-70s. There’s a 50 percent chance of scattered thunderstorms throughout the region, and the NWS seven-day forecast reports lows of 76 to 75 degrees stretching from Sunday through next Thursday. Highs during this period won’t even reach 96 degrees, a welcome break for many after weeks of triple-digit heat.
Rainfall totals through Labor Day could range from a quarter-inch to an inch, but isolated totals of more than 2 to 3 inches are possible, especially in areas hit by stronger storms. This raises the risk of flash flooding, though the NWS notes that the flooding threat for San Antonio is currently assessed as level one out of four, with more severe conditions possible west of the city. Locals are advised to stay alert for any weather warnings as the weekend approaches, since the situation could evolve rapidly.
The main driver behind the incoming front is a shift in wind direction. As the front moves in, winds will turn to the north, bringing slightly drier air and a much-needed drop in temperatures—about 10 degrees cooler than the preceding days. “It’ll be cooler behind that front as we get into Monday and Tuesday, with highs in the lower 90s,” a local meteorologist told MySA. “It won’t be like the sharp cold front like we’re used to in the fall or winter, but definitely cooler.”
By Tuesday, September 2, rain chances begin to taper off, with a 20 percent chance of precipitation and temperatures stabilizing in the low 90s. Wednesday, September 3, is expected to bring mostly sunny skies and highs near 95 degrees, signaling a return to more typical late-summer weather for the region. Rain and storm chances will be low—just 10 to 30 percent—by midweek, with most of the activity shifting toward the Rio Grande area.
For San Antonio, the upcoming days will be a test of endurance as the city waits out the last gasp of summer heat and looks forward to the promise of cooler, wetter weather. While the relief may be gradual and the threat of storms brings its own risks, many residents will be watching the skies this Labor Day weekend, hoping that the forecasted showers finally put an end to the relentless heatwave.
