Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 78253 — San Antonio, TX

ZIP code 78253 (San Antonio, Bexar County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is February 18 and the first fall frost December 9.

Where ZIP 78253 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone9a20 to 25 °F
Coldest night−6.7 to −3.9 °C
Last frostFeb 18
First frostDec 9
2012 zone9a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for San Antonio, TX…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in San Antonio, TX

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 18median — 50% chance of a later frost
Safe for tender plantsMarch 16only 10% chance of frost after
First fall frostDecember 9median — 10% chance by Nov 17
Growing season296 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 31 and returns around December 29.

From the NOAA station San Antonio/Seaworld, TX — 5 miles away, elevation 942 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 78253

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 7 – Jan 21
SpinachSow outdoors · Jan 7 – Jan 28
Broccoli, cabbageStart indoors · Dec 10 – Dec 24
Broccoli, cabbageTransplant · Jan 28 – Feb 11
Onion setsPlant outdoors · Jan 21 – Feb 4
PotatoesPlant outdoors · Jan 28 – Feb 11
LettuceSow outdoors · Jan 21 – Feb 4
Carrots, beetsSow outdoors · Jan 28 – Feb 11
TomatoesStart indoors · Dec 24 – Jan 7
TomatoesTransplant · Feb 25 – Mar 11
Peppers, eggplantStart indoors · Dec 10 – Dec 24
Peppers, eggplantTransplant · Mar 4 – Mar 18
BeansSow outdoors · Feb 25 – Mar 11
Sweet cornSow outdoors · Feb 25 – Mar 11
Cucumbers, squashSow outdoors · Feb 25 – Mar 11
Fall lettuce, spinachSow outdoors · Oct 14 – Oct 28
GarlicPlant cloves · Nov 25 – Dec 30
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 18) and first fall frost (Dec 9) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 78253 came on Jan 20 — 5 days earlier than the 1991–2020 average (Jan 25).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in San Antonio, TX

The soil mapped at the center of ZIP 78253 is Eckrant — cobbly clay, well drained.

TextureCobbly clayholds water and nutrients; slow to drain and warm up
pH7.3neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter6%high
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Eckrant cobbly clay, 1 to 8 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 78253; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Antonio, TX

Summer high99 °Faverage high, August
Winter low43 °Faverage low, January
Hot days123days a year at 90 °F or more
Freezing nights14nights a year at 32 °F or less
Growing degree days7,892base 50 °F — the season’s usable heat
Longest day14 h 02 mindaylight on June 21
Shortest day10 h 15 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation34 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 65 °F, low 43 °F 65°43° JanFebruary: average high 70 °F, low 46 °F 70°46° FebMarch: average high 76 °F, low 53 °F 76°53° MarApril: average high 83 °F, low 60 °F 83°60° AprMay: average high 89 °F, low 67 °F 89°67° MayJune: average high 95 °F, low 73 °F 95°73° JunJuly: average high 97 °F, low 74 °F 97°74° JulAugust: average high 99 °F, low 74 °F 99°74° AugSeptember: average high 93 °F, low 70 °F 93°70° SepOctober: average high 85 °F, low 62 °F 85°62° OctNovember: average high 74 °F, low 51 °F 74°51° NovDecember: average high 66 °F, low 44 °F 66°44° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 1.87 in precipitation 1.9 JanFebruary: 1.78 in precipitation 1.8 FebMarch: 2.44 in precipitation 2.4 MarApril: 2.49 in precipitation 2.5 AprMay: 4.45 in precipitation 4.5 MayJune: 3.75 in precipitation 3.8 JunJuly: 2.61 in precipitation 2.6 JulAugust: 3.04 in precipitation 3.0 AugSeptember: 3.54 in precipitation 3.5 SepOctober: 3.60 in precipitation 3.6 OctNovember: 2.49 in precipitation 2.5 NovDecember: 1.89 in precipitation 1.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: San Antonio/Seaworld, TX (5 mi away); precipitation: Castroville 7.0 Nne, TX (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9a.

782549a
San Antonio, TX · 6 mi
782459a
San Antonio, TX · 6 mi
780669a
Rio Medina, TX · 6 mi
782519a
San Antonio, TX · 7 mi
782509a
San Antonio, TX · 8 mi
780099a
Castroville, TX · 9 mi
782389a
San Antonio, TX · 10 mi
782279a
San Antonio, TX · 11 mi

All 82 ZIP codes in San Antonio → · Texas planting zones →

Questions about 78253

What planting zone is ZIP code 78253?

ZIP code 78253 (San Antonio, TX) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in San Antonio, TX?

The median last spring frost (32 °F) near 78253 is February 18; after March 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, San Antonio/Seaworld station.

When is the first frost in San Antonio, TX?

The median first fall frost near 78253 is December 9, giving a median frost-free growing season of 296 days.

When should I plant tomatoes in 78253?

Start tomato seeds indoors around Dec 24 – Jan 7 and set transplants outside around Feb 25 – Mar 11, one to three weeks after the median last frost.

How much rain and snow does 78253 get?

About 34 inches of precipitation a year (NOAA 1991–2020 normals, Castroville 7.0 Nne station).

How hot do summers get in San Antonio, TX?

The average high peaks at 99 °F in August, with about 123 days a year at 90 °F or more.

What kind of soil does 78253 have?

The USDA soil survey maps Eckrant at the center of ZIP 78253: cobbly clay, well drained, pH about 7.3 (neutral).

Did spring come early in San Antonio, TX in 2026?

Spring leaf-out near 78253 came on Jan 20 in 2026, 5 days earlier than the 1991–2020 average (Jan 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in San Antonio, TX?

Short-day onions: the longest day near 78253 is 14 h 02 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.