Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 76537 — Jarrell, TX

ZIP code 76537 (Jarrell, Williamson County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is March 6 and the first fall frost November 24.

Where ZIP 76537 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.

Zone8b15 to 20 °F

Coldest night−9.4 to −6.7 °C

Last frostMar 6

First frostNov 24

2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Jarrell, 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 Jarrell, TX

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMarch 6median — 50% chance of a later frost

Safe for tender plantsMarch 30only 10% chance of frost after

First fall frostNovember 24median — 10% chance by Nov 5

Growing season259 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 23 and returns around December 5.

From the NOAA station Georgetown Lake, TX — 12 miles away, elevation 873 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 76537

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 23 – Feb 6

SpinachSow outdoors · Jan 23 – Feb 13

Broccoli, cabbageStart indoors · Dec 26 – Jan 9

Broccoli, cabbageTransplant · Feb 13 – Feb 27

Onion setsPlant outdoors · Feb 6 – Feb 20

PotatoesPlant outdoors · Feb 13 – Feb 27

LettuceSow outdoors · Feb 6 – Feb 20

Carrots, beetsSow outdoors · Feb 13 – Feb 27

TomatoesStart indoors · Jan 9 – Jan 23

TomatoesTransplant · Mar 13 – Mar 27

Peppers, eggplantStart indoors · Dec 26 – Jan 9

Peppers, eggplantTransplant · Mar 20 – Apr 3

BeansSow outdoors · Mar 13 – Mar 27

Sweet cornSow outdoors · Mar 13 – Mar 27

Cucumbers, squashSow outdoors · Mar 13 – Mar 27

Fall lettuce, spinachSow outdoors · Sep 29 – Oct 13

GarlicPlant cloves · Nov 10 – Dec 15

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 6) and first fall frost (Nov 24) 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 76537 came on Jan 30 — about the same time as the 1991–2020 average (Jan 30).

average
Jan 302026
Jan 30

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 Jarrell, TX

The soil mapped at the center of ZIP 76537 is Castephen — silty clay, well drained.

TextureSilty clayholds water and nutrients; slow to drain and warm up

pH8.2alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Castephen silty clay, 3 to 5 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 76537; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Jarrell, TX

Summer high97 °Faverage high, August

Winter low36 °Faverage low, January

Hot days112days a year at 90 °F or more

Freezing nights28nights a year at 32 °F or less

Growing degree days6,670base 50 °F — the season’s usable heat

Longest day14 h 09 mindaylight on June 21

Shortest day10 h 09 mindaylight on December 21

Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb

Precipitation35.9 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Georgetown Lake, TX (12 mi away); precipitation: Jarrell, TX (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

786738b

Walburg, TX · 5 mi

765738b

Schwertner, TX · 6 mi

Georgetown, TX · 11 mi

765119a

Bartlett, TX · 11 mi

786269a

Georgetown, TX · 11 mi

786809a

Round Rock, TX · 11 mi

Texas planting zones →

Questions about 76537

What planting zone is ZIP code 76537?

ZIP code 76537 (Jarrell, TX) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Jarrell, TX?

The median last spring frost (32 °F) near 76537 is March 6; after March 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Georgetown Lake station.

When is the first frost in Jarrell, TX?

The median first fall frost near 76537 is November 24, giving a median frost-free growing season of 259 days.

When should I plant tomatoes in 76537?

Start tomato seeds indoors around Jan 9 – Jan 23 and set transplants outside around Mar 13 – Mar 27, one to three weeks after the median last frost.

How much rain and snow does 76537 get?

About 35.9 inches of precipitation a year (NOAA 1991–2020 normals, Jarrell station).

How hot do summers get in Jarrell, TX?

The average high peaks at 97 °F in August, with about 112 days a year at 90 °F or more.

What kind of soil does 76537 have?

The USDA soil survey maps Castephen at the center of ZIP 76537: silty clay, well drained, pH about 8.2 (alkaline).

Did spring come early in Jarrell, TX in 2026?

Spring leaf-out near 76537 came on Jan 30 in 2026, about the same as the 1991–2020 average (Jan 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Jarrell, TX?

Short-day onions: the longest day near 76537 is 14 h 09 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.