USDA Hardiness Zone 9a
Frost Dates for 77833 — Brenham, Texas
NOAA 1991–2020 normals from Brenham, TX (313 ft), 2 miles south.
Updated
In Brenham, the last spring frost (32°F) is around March 2 in half of years and has passed by March 20 in nine years out of ten. The first fall frost comes around November 30, as early as November 8 one year in ten, leaving a typical freeze-free season of 273 days (NOAA, Brenham, TX).
- Last spring frost
- March 2
- First fall frost
- November 30
- Growing season
- 273 days
- Hardiness zone
- 9a
50% probability
50% probability
freeze-free, 50%
20 to 25°F (-6.7 to -3.9°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
0 of 23 observed
NOAA normal
Frost risk by date in Brenham
Half of springs at Brenham, TX see their last 32°F night by March 2; only one in ten is past it by January 31, and one in ten still has one after March 20. Planting tender crops after March 9 leaves a 30% risk of a frost on them, after March 14 20%, and after March 20 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 75% of the 339 Texas stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 30 in half of years, as early as November 8 one year in ten, and holds off past December 23 one year in ten. A hard freeze of 28°F follows 18 days later, around December 18; in spring the one-in-ten date for 28°F is March 11, 9 days before the 32°F one. The freeze-free season lasts 273 days in a typical year, longer than at 73% of the 339 Texas stations; it reaches 306 days one year in ten and falls short of 242 one year in ten. On average 18 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about March 13, and return around November 17. Nights of 24°F, cold enough to damage hardier plants, come in 67% of winters and 16°F in 5%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 23 | Mar 1 | Mar 5 | Mar 9 | Mar 13 | Mar 17 | Mar 21 | Mar 27 | Apr 1 |
| 32°F | Jan 31 | Feb 12 | Feb 19 | Feb 27 | Mar 2 | Mar 5 | Mar 9 | Mar 14 | Mar 20 |
| 28°F96% of yrs | Jan 6 | Jan 20 | Jan 28 | Feb 2 | Feb 10 | Feb 19 | Feb 27 | Mar 4 | Mar 11 |
| 24°F67% of yrs | Dec 21 | Jan 2 | Jan 10 | Jan 19 | Jan 25 | Jan 31 | Feb 6 | Feb 20 | Mar 3 |
| 20°F27% of yrs | too rare for a date | ||||||||
| 16°F5% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 1 | Nov 5 | Nov 9 | Nov 13 | Nov 17 | Nov 21 | Nov 26 | Dec 1 | Dec 5 |
| 32°F | Nov 8 | Nov 15 | Nov 21 | Nov 26 | Nov 30 | Dec 3 | Dec 8 | Dec 14 | Dec 23 |
| 28°F96% of yrs | Nov 18 | Nov 28 | Dec 4 | Dec 9 | Dec 18 | Dec 25 | Jan 1 | Jan 6 | Jan 19 |
| 24°F67% of yrs | Dec 4 | Dec 12 | Dec 22 | Dec 30 | Jan 3 | Jan 7 | Jan 14 | Jan 20 | Feb 4 |
| 20°F27% of yrs | too rare for a date | ||||||||
| 16°F5% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Brenham, TX, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 77833 →Compare Brenham with another place →
Weather by month in Brenham
August is the warmest month at Brenham, TX, averaging 95°F by day and 74°F at night; January is the coldest at 61°F and 40°F. A freezing night is all but certain in January (a 90% chance or more). From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 78% of years and March still brings one in 54% of years.
Warmth for growing adds up to 6,914 growing degree days a year (base 50°F), more than at 66% of the 351 Texas stations. 41% of them (2,856) have built up by the end of June, and August adds the most, 1,065. Precipitation totals 48.2 inches a year, most in May (5.4") and least in July (2.6"); May to September bring 43% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 61 | 40 | 3.7 | 94% | 6 | 123 |
| Feb | 64 | 43 | 3.4 | 78% | 3 | 167 |
| Mar | 71 | 49 | 3.6 | 54% | 1 | 335 |
| Apr | 78 | 57 | 3.6 | 1% | 0 | 522 |
| May | 85 | 65 | 5.4 | 0% | 0 | 772 |
| Jun | 91 | 72 | 4.5 | 0% | 0 | 937 |
| Jul | 94 | 74 | 2.6 | 0% | 0 | 1046 |
| Aug | 95 | 74 | 3.8 | 0% | 0 | 1065 |
| Sep | 90 | 68 | 4.6 | 0% | 0 | 873 |
| Oct | 81 | 59 | 5.1 | 3% | 0 | 620 |
| Nov | 70 | 48 | 4.2 | 49% | 2 | 303 |
| Dec | 63 | 41 | 3.7 | 87% | 5 | 151 |
Monthly normals 1991–2020 at Brenham, TX (313 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Somerville Dam, TX, 13 miles northwest of Brenham, has a last frost 16 days later (March 18), a first frost 21 days earlier (November 9), a season 35 days shorter.
When it snows in Brenham, Texas
Measurable snow is rare here: only 0 of 23 winters from 1991 to 2020 recorded 0.1 inch or more at Brenham, TX, 1.7 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 77833
| When | What to do |
|---|---|
| December 22 – January 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 5 – January 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 2 – February 16 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 16 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 30 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 77833 is 2 miles from Brenham, TX, which stands at 313 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 77833 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.