USDA Hardiness Zone 9b
Frost Dates for 77049 — Houston, Texas
NOAA 1991–2020 normals from Houston-Port, TX (19 ft), 9 miles southwest.
Updated
In Houston, the last spring frost (32°F) is around February 2 in half of years and has passed by March 5 in nine years out of ten. The first fall frost comes around December 25, as early as November 27 one year in ten, leaving a typical freeze-free season of 327 days (NOAA, Houston-Port, TX).
- Last spring frost
- February 2
- First fall frost
- December 25
- Growing season
- 327 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
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 16 observed
NOAA normal
Frost risk by date in Houston
Half of springs at Houston-Port, TX see their last 32°F night by February 2; only one in ten is past it by December 31, and one in ten still has one after March 5. Planting tender crops after February 18 leaves a 30% risk of a frost on them, after February 28 20%, and after March 5 10%. The 31 days between the even-odds date and the one-in-ten date is wider than at 92% 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 25 in half of years, as early as November 27 one year in ten, and holds off past January 21 one year in ten. A hard freeze of 28°F follows 11 days later, around January 5; in spring the one-in-ten date for 28°F is February 25, 8 days before the 32°F one. The freeze-free season lasts 327 days in a typical year, longer than at 93% of the 339 Texas stations; it reaches 365 days one year in ten and falls short of 285 one year in ten. On average 5 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 22 days longer, to about February 24, and return around December 2. A 24°F night is unusual: 18% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 22 | Jan 31 | Feb 8 | Feb 17 | Feb 24 | Feb 28 | Mar 4 | Mar 9 | Mar 16 |
| 32°F90% of yrs | Dec 31 | Jan 13 | Jan 21 | Jan 28 | Feb 2 | Feb 9 | Feb 18 | Feb 28 | Mar 5 |
| 28°F55% of yrs | Dec 24 | Jan 2 | Jan 11 | Jan 17 | Jan 23 | Jan 27 | Feb 2 | Feb 11 | Feb 25 |
| 24°F18% of yrs | too rare for a date | ||||||||
| 20°F4% 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 12 | Nov 19 | Nov 25 | Nov 30 | Dec 2 | Dec 7 | Dec 13 | Dec 22 | Jan 1 |
| 32°F90% of yrs | Nov 27 | Dec 2 | Dec 8 | Dec 17 | Dec 25 | Dec 31 | Jan 4 | Jan 10 | Jan 21 |
| 28°F55% of yrs | Dec 8 | Dec 19 | Dec 28 | Jan 1 | Jan 5 | Jan 10 | Jan 16 | Jan 26 | Feb 9 |
| 24°F18% of yrs | too rare for a date | ||||||||
| 20°F4% of yrs | too rare for a date | ||||||||
| 16°F0% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Houston-Port, 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 77049 →Compare Houston with another place →
Weather by month in Houston
August is the warmest month at Houston-Port, TX, averaging 94°F by day and 77°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 38% of years and March still brings one in 15% of years.
Warmth for growing adds up to 7,687 growing degree days a year (base 50°F), more than at 82% of the 351 Texas stations. 43% of them (3,282) have built up by the end of June, and August adds the most, 1,102. Precipitation totals 54.3 inches a year, most in June (7.9") and least in February (2.8"); 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 | 4.0 | 67% | 2 | 177 |
| Feb | 67 | 49 | 2.8 | 38% | 1 | 244 |
| Mar | 73 | 54 | 3.8 | 15% | <1 | 425 |
| Apr | 79 | 61 | 5.2 | 0% | 0 | 602 |
| May | 86 | 69 | 5.1 | 0% | 0 | 843 |
| Jun | 91 | 75 | 7.9 | 0% | 0 | 991 |
| Jul | 93 | 77 | 4.5 | 0% | 0 | 1085 |
| Aug | 94 | 77 | 3.4 | 0% | 0 | 1102 |
| Sep | 90 | 72 | 4.5 | 0% | 0 | 924 |
| Oct | 82 | 63 | 5.4 | 0% | 0 | 692 |
| Nov | 72 | 53 | 3.4 | 13% | <1 | 385 |
| Dec | 65 | 46 | 4.3 | 47% | 1 | 217 |
Monthly normals 1991–2020 at Houston-Port, TX (19 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, Baytown, TX, 12 miles northeast of Houston, has a last frost 18 days later (February 20), a first frost 21 days earlier (December 4), a season 35 days shorter.
When it snows in Houston, Texas
Measurable snow is rare here: only 0 of 16 winters from 1991 to 2020 recorded 0.1 inch or more at Houston-Port, TX, 8.7 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 77049
| When | What to do |
|---|---|
| November 24 – December 8 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 8 – December 22 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 5 – January 19 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by October 2 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by December 11 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 25 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 77049 is 9 miles from Houston-Port, TX, which stands at 19 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 34 other ZIP codes share the station; its figures are presented in full for 77015 (Houston). The 2023 USDA Plant Hardiness Zone Map lists ZIP 77049 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.