Do I need to cover plants for frost in San Antonio, TX this week?
Here's the next 7 days for covering plants in San Antonio, checked hour by hour against the published thresholds. Below it: what San Antonio's 1991–2020 climate averages say about the months that usually work.
This week in San Antonio
Asking the sky…
Fairsky is not a substitute for official warnings. For warnings, go to weather.gov. Verdicts are guidance, not guarantees. Your product's label always wins.
When covering plants usually works in San Antonio
- On 1991–2020 averages, San Antonio's median last spring freeze (32°F) comes around February 25 and the median first fall freeze around November 28. In half of years the date is later than that, in half earlier.
- Nights of 36°F or colder, when frost can form under clear, calm skies, typically end around March 10 and return around November 16.
- Hard freezes (28°F or colder, which kill most tender plants even under a cover) typically end around February 5 and return around December 15.
- San Antonio averages 22 nights a year at or below 32°F, most of them in December (8.4).
| Month | Avg high | Avg low | Days ≥0.10" rain | Nights ≤32°F |
|---|---|---|---|---|
| January | 63° | 40° | 3.7 | 6.8 |
| February | 68° | 44° | 3.3 | 4.2 |
| March | 74° | 51° | 4.1 | 0.8 |
| April | 80° | 57° | 2.9 | 0.0 |
| May | 86° | 66° | 4.3 | 0.0 |
| June | 92° | 72° | 4.1 | 0.0 |
| July | 94° | 74° | 4.2 | 0.0 |
| August | 95° | 74° | 2.8 | 0.0 |
| September | 90° | 69° | 5.4 | 0.0 |
| October | 82° | 59° | 4.6 | 0.1 |
| November | 71° | 49° | 3.4 | 1.6 |
| December | 64° | 41° | 3.7 | 8.4 |
Station: San Antonio Incarnate Word (NOAA NCEI USC00417947), about 6 km from central San Antonio. “Rain days” count days with 0.10" or more of precipitation.
The rules we check
- Cover tender plants when the overnight low is forecast at 34°F or colder.
- At 35–36°F, Fairsky still says cover when the night looks clear and calm (little cloud, wind 5 mph or less), because the ground can frost before the air hits 32°F. (Fairsky default: no source gave a number)
- 32°F or colder is a freeze.
- 28°F or colder is a hard freeze, which kills most tender vegetation; bring pots inside, since covers may not be enough.
Your product's label always wins. Labels differ by product; in the app you can enter your label's temperature range and rain-free hours, and the verdict uses them instead.
Sources: NWS glossary: frost advisory · NWS glossary: hard freeze
More home and yard jobs in San Antonio
- Stain a deckDeck and fence stain: 50–90°F, dry wood, 24 rain-free hours after.
- Paint a house exteriorExterior latex paint: 40°F and up, 5°F above the dew point, 4 dry hours after.
- Pour concreteConcrete: 40–85°F, no rain for 24 hours, no freezing for 48.
- Spray weedsWeed killer: 3–10 mph wind, 45–85°F, 4 rain-free hours after.
- Apply pre-emergentCrabgrass pre-emergent: before soil holds 55°F (about 200 GDD), then water it in.
- Plant grass seedCool-season grass seed: soil about 50–65°F, highs 60–80°F, no washout rain.
- Seal a drivewayAsphalt sealcoat: 55°F and rising, 50°F overnight, 36 rain-free hours.
The app covers 47 activities in all, from mowing to a round of golf: see every activity and its rules.
Cover plants for frost in nearby cities
- Austin, TX74 miles away
- Houston, TX189 miles away
- McAllen, TX223 miles away
- Dallas, TX252 miles away
- Oklahoma City, OK421 miles away
- Baton Rouge, LA443 miles away
All cover plants for frost cities: Cover plants for frost, by city · Home and yard in Texas
Questions
How is this verdict made?
We take the National Weather Service hourly forecast for San Antonio and check each hour against the thresholds listed above. The result is guidance, not a guarantee; your product's label always wins.
Will it frost tonight in San Antonio?
Frost is possible when the forecast low is in the mid-30s °F or colder, especially on clear, calm nights. The verdict above checks San Antonio's low tonight and this week.
Fairsky is not a substitute for official warnings. For warnings, go to weather.gov.
Live forecasts: National Weather Service / NOAA (public domain), fetched by your browser. Climate averages: NOAA NCEI U.S. Climate Normals, 1991–2020 (public domain). Activity thresholds: product data sheets, ACI and university extension guidance, linked on each page; your product’s label wins.