Frost dates · USDA zone 9a
Frost dates for Round Rock, TX
Round Rock, TX sees its last 32 °F night of spring around March 11 and its first of fall around November 20 — a 254-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Feb 22 | Dec 9 |
| Median — 1 year in 2 | Mar 11 | Nov 20 |
| 1 year in 10 | Mar 29 | Nov 3 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 254 days median, at least 230 in 9 years of 10, at least 278 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Mar 1 and first of Dec 3.
Round Rock planting calendar, 2027
Every row runs from the median last frost (Mar 11) and median first frost (Nov 20) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Dec 17 | Feb 11 | Jun 1 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Mar 11 | Apr 10 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Feb 25 | Feb 25 | Apr 11 | 45 from sow |
| Genovese BasilGenovese | Feb 11 | Mar 25 | May 24 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Jan 14 | Mar 18 | Jun 1 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Dec 31 | Mar 25 | Jun 28 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Jan 14 | Mar 18 | Jun 1 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Jan 14 | Mar 18 | Jun 6 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Jan 14 | Mar 18 | Jun 6 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Feb 25 | Feb 25 | May 6 | 70 from sow |
| TomatilloToma Verde | Jan 28 | Mar 18 | May 27 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Jan 28 | Mar 18 | Jun 1 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Jan 28 | Mar 18 | Jun 6 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Round Rock grow?
Each sauce, scheduled for a Round Rock container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Round Rock frost questions
When is the last frost in Round Rock, TX?
The median last 32 °F freeze at AUSTIN GREAT HILLS, TX is March 11: half of years see a later one. One year in ten, a freeze still comes after March 29; nine years in ten, it comes after February 22. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Round Rock, TX?
The median first 32 °F freeze of fall is November 20. One year in ten it arrives before November 3; nine years in ten, before December 9.
How long is the growing season in Round Rock, TX?
254 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 230 days; one year in ten, at least 278 days.
What growing zone is Round Rock, TX?
USDA hardiness zone 9a, per the 2023 USDA Plant Hardiness Zone Map for ZIP 78664. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Round Rock, TX?
Start Roma VF (determinate paste) seeds indoors around Jan 28 and transplant around Mar 18, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Mar 29. First ripe fruit lands around Jun 1.
When should I plant peppers in Round Rock, TX?
Sow jalapeño indoors on a heat mat around Jan 14; transplant no earlier than Mar 18, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jun 1.
Nearby in Texas
- Pflugervillelast frost Mar 11
- Huttolast frost Mar 8
- Cedar Parklast frost Mar 11
- Georgetownlast frost Mar 6
- Leanderlast frost Mar 2
- Austinlast frost Feb 20
All Texas frost dates → · How frost-date math drives a sowing calendar →