When is the last frost in Round Rock, TX?

The average last spring frost (50% probability of 32°F) in Round Rock is around March 11, based on NOAA/NCEI 1991–2020 normals at the Austin Great Hills, TX station (9.5 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Round Rock?

The average first fall frost in Round Rock, TX is around November 20, giving roughly a 254-day frost-free growing season.

What planting zone is Round Rock, TX?

Round Rock is in USDA plant hardiness zone 9a (average annual extreme minimum temperature 20 to 25°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Round Rock?

In Round Rock, TX the warmest month is August (avg high 96.8°F) and the coldest is January (avg low 36.2°F). It averages about 37.1″ of precipitation a year.

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Round Rock, TX Planting Calendar & Frost Dates

USDA hardiness zone 9a · ZIP 78664 · elevation 266′ · NOAA & USDA data

Round Rock is in USDA hardiness zone 9a (winters can dip to 20 to 25°F), with a growing season of about 254 days between the average last spring frost (March 11) and first fall frost (November 20). The warmest month is August (avg high 96.8°F); the coldest is January (avg low 36.2°F). It averages 37.1″ of precipitation a year. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 20 to 25°F

Last spring frost

March 11

avg (50% prob, 32°F)

First fall frost

November 20

avg (50% prob, 32°F)

Growing season

254 days

frost-free window

Warmest month

August

avg high 96.8°F

Month-by-month typical weather in Round Rock

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Georgetown Lake, TX (12.6 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)
January	60.3	36.2	48.3	2.5
February	64.6	40.1	52.3	2.2
March	71.5	47.2	59.4	3.1
April	78.6	54.2	66.4	3
May	85.4	63.4	74.4	4.3
June	92	69.5	80.7	4
July	95.9	72.2	84.1	2.2
August	96.8	72	84.4	2.6
September	90.1	66.5	78.3	4
October	81.3	56.8	69	3.9
November	69.8	46.3	58.1	2.7
December	61.7	38.2	49.9	2.6

What to plant when in Round Rock

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: January 28 · Transplant out: March 18
Peppers	warm	Start seeds indoors: January 14 · Transplant out: March 25
Cucumbers	warm	Direct sow: March 18
Zucchini / squash	warm	Direct sow: March 18
Bush beans	warm	Direct sow: March 18
Sweet corn	warm	Direct sow: March 18
Basil	warm	Transplant out: March 18
Peas	cool	Sow (spring): February 4 · Sow (fall): September 25
Spinach	cool	Sow (spring): January 28 · Sow (fall): September 25
Lettuce	cool	Sow (spring): February 11 · Sow (fall): September 25
Kale	cool	Transplant (spring): February 18 · Sow (fall): September 11
Broccoli	cool	Transplant (spring): February 25
Carrots	cool	Sow (spring): February 18 · Sow (fall): September 11
Onions	cool	Transplant (spring): February 11
Potatoes	cool	Plant seed potatoes: February 25
Radishes	cool	Sow (spring): February 11 · Sow (fall): October 9

Dates are computed from Round Rock's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Texas

Pflugerville, TX Cedar Park, TX Georgetown, TX Austin, TX Killeen, TX Temple, TX San Marcos, TX New Braunfels, TX

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Austin Great Hills, TX, 9.5 mi (confidence: high). Monthly weather normals: Georgetown Lake, TX, 12.6 mi (confidence: medium). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.