USDA Hardiness Zone 9b
Frost Dates for 77511 — Alvin, Texas
NOAA 1991–2020 normals from Alvin, TX (28 ft), 3 miles south.
Updated
In Alvin, the last spring frost (32°F) is around February 14 in half of years and has passed by March 13 in nine years out of ten. The first fall frost comes around December 5, as early as November 14 one year in ten, leaving a typical freeze-free season of 298 days (NOAA, Alvin, TX).
- Last spring frost
- February 14
- First fall frost
- December 5
- Growing season
- 298 days
- Hardiness zone
- 9b
50% probability
50% probability
freeze-free, 50%
25 to 30°F (-3.9 to -1.1°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 15%
- Snow per year
- 0.2"
median, 1991–2020
median, 1991–2020
3 of 20 observed
NOAA normal
Frost risk by date in Alvin
Half of springs at Alvin, TX see their last 32°F night by February 14; only one in ten is past it by January 15, and one in ten still has one after March 13. Planting tender crops after February 28 leaves a 30% risk of a frost on them, after March 6 20%, and after March 13 10%. The 27 days between the even-odds date and the one-in-ten date is wider than at 86% of the 339 Texas stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by December 5 in half of years, as early as November 14 one year in ten, and holds off past January 8 one year in ten. A hard freeze of 28°F follows 25 days later, around December 30; in spring the one-in-ten date for 28°F is March 2, 11 days before the 32°F one. The freeze-free season lasts 298 days in a typical year, longer than at 86% of the 339 Texas stations; it reaches 335 days one year in ten and falls short of 261 one year in ten. On average 10 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 19 days longer, to about March 5, and return around November 23. A 24°F night is unusual: 42% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 4 | Feb 17 | Feb 24 | Feb 28 | Mar 5 | Mar 9 | Mar 14 | Mar 18 | Mar 27 |
| 32°F99% of yrs | Jan 15 | Jan 24 | Jan 31 | Feb 5 | Feb 14 | Feb 23 | Feb 28 | Mar 6 | Mar 13 |
| 28°F84% of yrs | Dec 23 | Jan 4 | Jan 13 | Jan 20 | Jan 25 | Jan 31 | Feb 7 | Feb 19 | Mar 2 |
| 24°F42% of yrs | too rare for a date | ||||||||
| 20°F10% of yrs | too rare for a date | ||||||||
| 16°F0% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 5 | Nov 10 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 6 | Dec 15 |
| 32°F99% of yrs | Nov 14 | Nov 21 | Nov 26 | Dec 1 | Dec 5 | Dec 10 | Dec 18 | Dec 31 | Jan 8 |
| 28°F84% of yrs | Nov 27 | Dec 3 | Dec 11 | Dec 20 | Dec 30 | Jan 3 | Jan 8 | Jan 16 | Feb 2 |
| 24°F42% of yrs | too rare for a date | ||||||||
| 20°F10% of yrs | too rare for a date | ||||||||
| 16°F0% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Alvin, 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 77511 →Compare Alvin with another place →
Weather by month in Alvin
August is the warmest month at Alvin, TX, averaging 91°F by day and 74°F at night; January is the coldest at 63°F and 44°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 55% of years and March still brings one in 29% of years.
Warmth for growing adds up to 7,224 growing degree days a year (base 50°F), more than at 74% of the 351 Texas stations. 43% of them (3,103) have built up by the end of June, and August adds the most, 1,009. Precipitation totals 55.1 inches a year, most in June (6.0") and least in February (3.0"); May to September bring 47% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 63 | 44 | 4.9 | 82% | 4 | 167 |
| Feb | 67 | 48 | 3.0 | 55% | 2 | 227 |
| Mar | 73 | 54 | 3.1 | 29% | 1 | 419 |
| Apr | 78 | 60 | 4.2 | 0% | 0 | 562 |
| May | 85 | 68 | 4.6 | 0% | 0 | 809 |
| Jun | 89 | 72 | 6.0 | 0% | 0 | 919 |
| Jul | 91 | 74 | 4.2 | 0% | 0 | 1006 |
| Aug | 91 | 74 | 5.6 | 0% | 0 | 1009 |
| Sep | 89 | 70 | 5.4 | 0% | 0 | 883 |
| Oct | 81 | 61 | 5.3 | 0% | 0 | 651 |
| Nov | 73 | 52 | 4.3 | 37% | 1 | 369 |
| Dec | 65 | 45 | 4.5 | 66% | 3 | 203 |
Monthly normals 1991–2020 at Alvin, TX (28 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, Houston Clover Field, TX, 7 miles north of Alvin, has a last frost 14 days earlier (January 31), a first frost 22 days later (December 27), a season 30 days longer.
When it snows in Alvin, Texas
Measurable snow is rare here: only 3 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Houston NWSO, TX, 10.6 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 77511
| When | What to do |
|---|---|
| December 6 – December 20 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 20 – January 3 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 17 – January 31 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 14 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 12 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 21 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 5 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 77511 is 3 miles from Alvin, TX, which stands at 28 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 77511 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°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.