USDA Hardiness Zone 9b
Frost Dates for 77045 — Houston, Texas
NOAA 1991–2020 normals from Houston Hobby Airport, TX (44 ft), 9 miles east.
Updated
A freeze (32°F) reaches Houston in 86% of winters. When it does, the first fall frost comes around December 28 and the last spring frost around January 30; after March 1 the chance of another is under 9%.
- Last spring frost
- January 30
- First fall frost
- December 28
- Winters with a freeze
- 86%
- Hardiness zone
- 9b
50%, in freezing years
50%, in freezing years
32°F or below, 1991–2020
25 to 30°F (-3.9 to -1.1°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 20 observed
NOAA normal
Frost risk by date in Houston
In the 86% of winters that bring a 32°F night, half of springs at Houston Hobby Airport, TX see their last 32°F night by January 30; only one in ten is past it by December 29, and one in ten still has one after March 1. Counting the winters with no freeze at all, the risk of a 32°F night after March 1 is under 9% and after January 30 43%. The 30 days between the even-odds date and the one-in-ten date is wider than at 91% 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 28 in half of years, as early as November 27 one year in ten, and holds off past January 27 one year in ten. A hard freeze of 28°F is less common: it came in 47% of winters. The freeze-free season lasts 330 days in a typical year, longer than at 95% of the 339 Texas stations; it reaches 365 days one year in ten and falls short of 292 one year in ten. On average 4 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 18 days longer, to about February 17, and return around December 4. A 24°F night is unusual: 14% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 20 | Jan 28 | Feb 4 | Feb 10 | Feb 17 | Feb 24 | Feb 28 | Mar 4 | Mar 12 |
| 32°F86% of yrs | Dec 29 | Jan 10 | Jan 18 | Jan 24 | Jan 30 | Feb 4 | Feb 10 | Feb 21 | Mar 1 |
| 28°F47% of yrs | too rare for a date | ||||||||
| 24°F14% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 15 | Nov 20 | Nov 25 | Nov 29 | Dec 4 | Dec 9 | Dec 16 | Dec 26 | Jan 3 |
| 32°F86% of yrs | Nov 27 | Dec 5 | Dec 10 | Dec 20 | Dec 28 | Jan 2 | Jan 7 | Jan 15 | Jan 27 |
| 28°F47% of yrs | too rare for a date | ||||||||
| 24°F14% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Houston Hobby Airport, 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 77045 →Compare Houston with another place →
Weather by month in Houston
August is the warmest month at Houston Hobby Airport, TX, averaging 94°F by day and 77°F at night; January is the coldest at 64°F and 46°F. From March to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 33% of years.
Warmth for growing adds up to 7,861 growing degree days a year (base 50°F), more than at 87% of the 351 Texas stations. 43% of them (3,393) have built up by the end of June, and August adds the most, 1,088. Precipitation totals 55.7 inches a year, most in June (6.1") and least in February (2.9"); May to September bring 49% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 64 | 46 | 4.1 | 61% | 2 | 204 |
| Feb | 68 | 50 | 2.9 | 33% | 1 | 269 |
| Mar | 73 | 56 | 3.3 | 10% | <1 | 459 |
| Apr | 79 | 62 | 4.1 | 0% | 0 | 617 |
| May | 86 | 69 | 5.4 | 0% | 0 | 856 |
| Jun | 91 | 75 | 6.1 | 0% | 0 | 988 |
| Jul | 93 | 77 | 4.6 | 0% | 0 | 1077 |
| Aug | 94 | 77 | 5.4 | 0% | 0 | 1088 |
| Sep | 89 | 73 | 5.8 | 0% | 0 | 933 |
| Oct | 82 | 64 | 5.8 | 0% | 0 | 713 |
| Nov | 73 | 54 | 3.9 | 11% | <1 | 408 |
| Dec | 66 | 48 | 4.3 | 39% | 1 | 248 |
Monthly normals 1991–2020 at Houston Hobby Airport, TX (44 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-Port, TX, 12 miles northeast of Houston, has a last frost 3 days later (February 2), a first frost 3 days earlier (December 25), a season 3 days shorter.
When it snows in Houston, Texas
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Houston Hts, TX, 11.2 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 77045 is 9 miles from Houston Hobby Airport, TX, which stands at 44 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 18 other ZIP codes share the station; its figures are presented in full for 77089 (Houston). The 2023 USDA Plant Hardiness Zone Map lists ZIP 77045 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.