USDA Hardiness Zone 9b
Frost Dates for 78387 — Sinton, Texas
NOAA 1991–2020 normals from Sinton, TX (48 ft), 2 miles southwest.
Updated
In Sinton, the last spring frost (32°F) is around February 1 in half of years and has passed by March 6 in nine years out of ten. The first fall frost comes around December 17, as early as November 22 one year in ten, leaving a typical freeze-free season of 324 days (NOAA, Sinton, TX).
- Last spring frost
- February 1
- First fall frost
- December 17
- Growing season
- 324 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
- 6%
- Snow per year
- 0.4"
median, 1991–2020
median, 1991–2020
1 of 18 observed
NOAA normal
Frost risk by date in Sinton
Half of springs at Sinton, TX see their last 32°F night by February 1; only one in ten is past it by December 27, and one in ten still has one after March 6. Planting tender crops after February 18 leaves a 30% risk of a frost on them, after February 28 20%, and after March 6 10%. The 33 days between the even-odds date and the one-in-ten date is wider than at 95% 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 17 in half of years, as early as November 22 one year in ten, and holds off past January 17 one year in ten. A hard freeze of 28°F follows 15 days later, around January 1; in spring the one-in-ten date for 28°F is February 24, 10 days before the 32°F one. The freeze-free season lasts 324 days in a typical year, longer than at 93% of the 339 Texas stations; it reaches 361 days one year in ten and falls short of 282 one year in ten. On average 7 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 24 days longer, to about February 25, and return around December 1. A 24°F night is unusual: 19% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 22 | Feb 1 | Feb 11 | Feb 18 | Feb 25 | Mar 1 | Mar 5 | Mar 9 | Mar 16 |
| 32°F93% of yrs | Dec 27 | Jan 7 | Jan 18 | Jan 26 | Feb 1 | Feb 9 | Feb 18 | Feb 28 | Mar 6 |
| 28°F58% of yrs | Dec 14 | Dec 25 | Jan 1 | Jan 7 | Jan 12 | Jan 22 | Jan 31 | Feb 7 | Feb 24 |
| 24°F19% of yrs | too rare for a date | ||||||||
| 20°F3% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 10 | Nov 16 | Nov 21 | Nov 27 | Dec 1 | Dec 4 | Dec 9 | Dec 17 | Dec 28 |
| 32°F93% of yrs | Nov 22 | Nov 30 | Dec 4 | Dec 9 | Dec 17 | Dec 24 | Dec 30 | Jan 5 | Jan 17 |
| 28°F58% of yrs | Dec 3 | Dec 11 | Dec 18 | Dec 26 | Jan 1 | Jan 4 | Jan 9 | Jan 18 | Feb 2 |
| 24°F19% of yrs | too rare for a date | ||||||||
| 20°F3% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Sinton, 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 78387 →Compare Sinton with another place →
Weather by month in Sinton
August is the warmest month at Sinton, TX, averaging 95°F by day and 76°F at night; January is the coldest at 66°F and 45°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 36% of years and March still brings one in 17% of years.
Warmth for growing adds up to 7,999 growing degree days a year (base 50°F), more than at 89% of the 351 Texas stations. 43% of them (3,473) have built up by the end of June, and August adds the most, 1,093. Precipitation totals 33.1 inches a year, most in September (5.3") and least in January (1.7"); May to September bring 52% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 66 | 45 | 1.7 | 65% | 3 | 224 |
| Feb | 70 | 49 | 1.9 | 36% | 1 | 293 |
| Mar | 75 | 56 | 2.4 | 17% | <1 | 484 |
| Apr | 81 | 62 | 1.8 | 0% | 0 | 636 |
| May | 86 | 69 | 3.3 | 0% | 0 | 856 |
| Jun | 91 | 74 | 3.4 | 0% | 0 | 981 |
| Jul | 93 | 76 | 2.8 | 0% | 0 | 1066 |
| Aug | 95 | 76 | 2.5 | 0% | 0 | 1093 |
| Sep | 90 | 71 | 5.3 | 0% | 0 | 926 |
| Oct | 85 | 63 | 3.9 | 0% | <1 | 735 |
| Nov | 75 | 54 | 2.4 | 19% | <1 | 443 |
| Dec | 68 | 47 | 1.7 | 58% | 2 | 263 |
Monthly normals 1991–2020 at Sinton, TX (48 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, Welder Wildlife Foundation, TX, 7 miles northeast of Sinton, has a last frost 23 days later (February 24), a first frost 16 days earlier (December 1), a season 41 days shorter.
When it snows in Sinton, Texas
Measurable snow is rare here: only 1 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Sinton, TX, 2 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 78387
| When | What to do |
|---|---|
| November 23 – December 7 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 7 – December 21 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 4 – January 18 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 1 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 24 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by December 3 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 17 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 78387 is 2 miles from Sinton, TX, which stands at 48 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 78387 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.