Frost dates / Texas / San Antonio

Frost dates in San Antonio, TX

The station on this page is SAN ANTONIO INCARNATE WORD, TX US (USC00417947), 3.2 miles from the city point. Population in the Census 2024 estimate is 1,526,656.

Zone 9aUSDA average annual extreme minimum 20°F to 25°F, from ZIP 78201 (0.5 miles from the city point used on this page).

Median last 32°F is February 25. Median first 32°F is November 28. The 50% growing-season length is 277 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

Probability	Date	How to read it
90%	January 28	Earlier date. A last 32°F on or after this day is common.
50%	February 25	Median.
10%	March 19	Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

Probability	Date	How to read it
10%	November 7	Earlier date. A first 32°F on or before this day is uncommon.
50%	November 28	Median.
90%	December 21	Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this long	Days
10%	313
50%	277
90%	249

28°F threshold

	10%	50%	90%
Last, on or after	March 5	February 5	December 31
First, on or before	November 19	December 15	January 20
Season at least	356 days	315 days	275 days

36°F threshold

	10%	50%	90%
Last, on or after	April 2	March 10	February 18
First, on or before	October 30	November 16	December 3
Season at least	279 days	251 days	223 days

Station SAN ANTONIO INCARNATE WORD, TX US (USC00417947). Completeness flag R, 16 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 213.4 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Planting calendar for San Antonio · Zone 9a

Check a crop against this station

San Antonio, TX

Zone 9aAverage annual extreme minimum 20°F to 25°F

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Texas. Nearest qualified station: SAN ANTONIO INCARNATE WORD, TX US (USC00417947), 3.2 miles. Median last 32°F February 25. Median first 32°F November 28. The 50% growing-season length is 277 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	March 19	February 25	January 28
First 32°F on or before	November 7	November 28	December 21

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

A wall calendar surrounded by vegetables, herbs, seed packets, and watering cans.

Planting calendar

Windows below are from Texas A&M AgriLife Extension, Texas Home Vegetable Gardening Guide, retrieved 2026-10-10. Table 8 is statewide and is written as weeks before or after the frost-free date (spring) and the first freeze date (fall). It is not a single calendar date for every Texas city.

Crop

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