Frost Dates for 78260 — San Antonio, Texas

Half of springs at San Antonio International Airport, TX see their last 32°F night by February 26; only one in ten is past it by January 29, and one in ten still has one after March 17. Planting tender crops after March 6 leaves a 30% risk of a frost on them, after March 10 20%, and after March 17 10%. The 19 days between the even-odds date and the one-in-ten date is narrower than at 63% of the 339 Texas stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 28 in half of years, as early as November 7 one year in ten, and holds off past December 22 one year in ten. A hard freeze of 28°F follows 15 days later, around December 13; in spring the one-in-ten date for 28°F is March 7, 10 days before the 32°F one. The freeze-free season lasts 277 days in a typical year, longer than at 76% of the 339 Texas stations; it reaches 311 days one year in ten and falls short of 247 one year in ten. On average 14 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 12 days longer, to about March 10, and return around November 16. Nights of 24°F, cold enough to damage hardier plants, come in 66% of winters and 16°F in 4%.

August is the warmest month at San Antonio International Airport, TX, averaging 96°F by day and 75°F at night; January is the coldest at 63°F and 41°F. A freezing night is all but certain in January (a 90% chance or more). From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 75% of years and March still brings one in 44% of years.

Warmth for growing adds up to 7,392 growing degree days a year (base 50°F), more than at 77% of the 351 Texas stations. 43% of them (3,144) have built up by the end of June, and August adds the most, 1,099. Precipitation totals 32.5 inches a year, most in May (4.4") and least in February (1.7"); May to September bring 50% of it.

The nearest other station, San Antonio Incarnate Word, TX, 16 miles south of San Antonio, has a last frost 1 day earlier (February 25), the same first-frost date.

Measurable snow is rare here: only 3 of 22 winters from 1991 to 2020 recorded 0.1 inch or more at Bulverde, TX, 2.7 miles away, so there is no typical first-snow date to plan around.

ZIP 78260 is 11 miles from San Antonio International Airport, TX, which stands at 789 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 16 other ZIP codes share the station; its figures are presented in full for 78249 (San Antonio). The 2023 USDA Plant Hardiness Zone Map lists ZIP 78260 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.