Frost dates / Texas / Round Rock
Frost dates in Round Rock, TX
The station on this page is AUSTIN GREAT HILLS, TX US (USC00410433), 9.9 miles from the city point. Population in the Census 2024 estimate is 135,359.
Zone 9aUSDA average annual extreme minimum 20°F to 25°F, from ZIP 78664 (1.7 miles from the city point used on this page).
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% | February 22 | Earlier date. A last 32°F on or after this day is common. |
| 50% | March 11 | Median. |
| 10% | March 29 | 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 3 | Earlier date. A first 32°F on or before this day is uncommon. |
| 50% | November 20 | Median. |
| 90% | December 9 | 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% | 278 |
| 50% | 254 |
| 90% | 230 |
28°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | March 19 | March 1 | January 31 |
| First, on or before | November 12 | December 3 | December 29 |
| Season at least | 309 days | 278 days | 252 days |
36°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | April 11 | March 25 | March 6 |
| First, on or before | October 27 | November 10 | November 27 |
| Season at least | 256 days | 231 days | 207 days |
Station AUSTIN GREAT HILLS, TX US (USC00410433). Completeness flag R, 13 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 268.2 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 Round Rock · Zone 9a
Check a crop against this station
Round Rock, 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: AUSTIN GREAT HILLS, TX US (USC00410433), 9.9 miles. Median last 32°F March 11. Median first 32°F November 20. The 50% growing-season length is 254 days.
Open the ZIP page · Crop guides for Texas
32°F probabilities at this station
| 10% | 50% | 90% | |
|---|---|---|---|
| Last 32°F on or after | March 29 | March 11 | February 22 |
| First 32°F on or before | November 3 | November 20 | December 9 |
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.
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.
Date checks use your device’s calendar and appear after the page loads.