If you’ve been living in San Antonio this winter, you’ve probably been waiting for the other shoe to drop. We coasted through the first half of January with temperatures that felt more like late October, but the honeymoon is officially over. The 10 day weather for San Antonio is finally bringing that reality check we all knew was coming. It’s not just a "light jacket" situation anymore; we are looking at a hard freeze and a messy transition into late January that’s going to catch a lot of people off guard.
Honestly, the city has been lucky. Up until this week, the San Antonio International Airport hadn't even recorded its first official freeze of 2026. That is wild. Usually, by now, we've had at least four or five nights where the birdbaths turn to ice. But as of January 17, the National Weather Service has issued a Red Flag Warning for today and a Freeze Warning for Sunday morning. The 10-day outlook shows a rollercoaster of bone-dry air followed by a moisture surge that might actually give our parched lawns a drink.
The Immediate Outlook: Fires and Freezes
Today is weird. It’s windy, it’s cool, and it’s dangerous. We have these gusts hitting 30 to 35 mph combined with very dry air. That is why the Red Flag Warning is in place. If a spark catches in the brush today, it’s going to go. Basically, don't do any outdoor burning. Just don't.
Tonight is when things get serious for your plants. A hard freeze is coming. Temperatures are expected to dip into the mid-20s across most of Bexar County. If you live in the Hill Country or out toward Boerne, you’re looking at even lower numbers. This isn't a "maybe" freeze; it's a "protect your pipes" freeze.
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- Saturday, Jan 17: High of 56°F. Blustery and dry.
- Sunday, Jan 18: High of 60°F after a low of 28°F. Sunny and crisp.
- Monday, Jan 19 (MLK Day): High 63°F, Low 46°F. Perfect for the march.
The MLK Day forecast is actually the highlight of the week. It’s going to be pleasant and cool, so if you're heading downtown, layers are your best friend. Start with a hoodie and you'll probably be down to a t-shirt by noon.
Why the Mid-Week Humidity is a Trap
Once we get past Monday, the atmosphere does a total 180. We go from that dry, Canadian air to a heavy Gulf flow. By Tuesday and Wednesday, rain chances jump to about 40% to 60%. It’s not going to be a washout, but it’ll be that annoying, misty San Antonio rain that makes the Loop 1604 commute a nightmare.
Tuesday stays cool with a high of 56°F, but the humidity will make it feel "raw." You know that feeling where the cold just sticks to your bones? That’s Tuesday. Wednesday warms up to 65°F, and that’s when the best chance for real rainfall arrives. We’ve been in a drought for years, so every drop counts, even if it ruins your car wash.
The Back Half of the 10-Day Window
Looking toward the end of the week, things level out. Thursday and Friday see highs in the upper 60s. By Saturday, Jan 24, we might even touch 70°F again. It’s classic San Antonio—you’ll use your heater and your A/C in the same 48-hour period.
But don't get too comfortable. The long-range data suggests another cool-down by Sunday, Jan 25. We aren't seeing any signs of a "Snowmaggedon" or a repeat of the 2021 grid failure, but the pattern is definitely shifting toward a more traditional, active winter.
The 10-Day Cheat Sheet
| Date | High/Low | The Vibe |
|---|---|---|
| Jan 17 | 56/28 | Windy and dangerous fire risk |
| Jan 18 | 60/38 | The first real hard freeze |
| Jan 19 | 63/46 | Perfect MLK Day weather |
| Jan 20 | 56/50 | Gray, damp, and gloomy |
| Jan 21 | 65/49 | Umbrella required; rain likely |
| Jan 22 | 66/44 | Clearing out and mild |
| Jan 23 | 68/58 | Spring-like and muggy |
| Jan 24 | 70/44 | Warmest day of the week |
| Jan 25 | 58/40 | Another front pushes through |
| Jan 26 | 65/44 | Calm and typical for January |
Understanding the La Niña Factor in 2026
You might be wondering why it took so long to get cold this year. The culprit is a fading La Niña. For the last few years, this pattern has kept the jet stream pushed north, leaving Texas high and dry.
Climatologists at the Climate Prediction Center are watching a transition to "ENSO-neutral" conditions. Basically, the Pacific Ocean is cooling down, which usually means our weather becomes less predictable. We are still leaning toward a warmer-than-average winter overall, but these short, sharp cold snaps—like the one we’re seeing tonight—are going to be more common as the season progresses.
Real Talk on the "4 P's"
Since we haven't had a real freeze yet this year, we’re all out of practice. You need to handle the 4 P's tonight before the sun goes down.
- People: Check on your neighbors, especially the elderly. Their heaters might be dust-covered and temperamental.
- Pets: If it's too cold for you, it's too cold for them. Bring the dogs inside.
- Plants: Anything in a pot needs to go in the garage. If it's in the ground, mulch it heavily and cover it with a cloth—not plastic. Plastic transfers the cold directly to the leaves.
- Pipes: Open your cabinet doors under the sinks to let the house heat reach the plumbing. If you have an outdoor faucet, wrap it in a towel or use one of those foam covers from H-E-B.
What Most People Get Wrong About San Antonio Winter
A lot of folks think that if it isn't snowing, the plants are safe. That’s a mistake. In South Texas, our plants aren't "hardened" to the cold like they are in Dallas or Oklahoma. A 25-degree night in San Antonio can kill a mature hibiscus that would survive easily further north because our sap stays flowing longer.
Also, don't trust the "average" temperature. The average high for January is 64°F, but that number is a lie. It’s an average of 80-degree days and 30-degree days. The 10 day weather for San Antonio proves that volatility is the only real constant here.
How to Handle the Next 10 Days
Don't panic about the freeze, but don't ignore it either. The dry wind today is actually more of a threat to your property than the cold tonight if you aren't careful with outdoor equipment or cigarettes. Once we hit the rain on Wednesday, the roads will be slick. San Antonio oil and dust build up on the asphalt during dry spells, making the first hour of rain incredibly slippery.
Next Steps for You:
- By Sunset Saturday: Cover your outdoor faucets and move sensitive succulents indoors.
- By Tuesday Morning: Check your windshield wipers; you're going to need them for the first time in weeks during the Wednesday commute.
- Long-term: Keep an eye on the late-January "punch" that the Farmer’s Almanac is predicting for the end of the month—this freeze might just be the opening act.