USDA Hardiness Zone 9a
Frost Dates for 78071 — Three Rivers, Texas
NOAA 1991–2020 normals from Choke Canyon Dam, TX (230 ft), 5 miles west.
Updated
In Three Rivers, the last spring frost (32°F) is around February 8 in half of years and has passed by March 8 in nine years out of ten. The first fall frost comes around December 6, as early as November 17 one year in ten, leaving a typical freeze-free season of 302 days (NOAA, Choke Canyon Dam, TX).
- Last spring frost
- February 8
- First fall frost
- December 6
- Growing season
- 302 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
- 8%
- Snow per year
- 0.3"
median, 1991–2020
median, 1991–2020
2 of 24 observed
NOAA normal
Frost risk by date in Three Rivers
Half of springs at Choke Canyon Dam, TX see their last 32°F night by February 8; only one in ten is past it by January 1, and one in ten still has one after March 8. Planting tender crops after February 22 leaves a 30% risk of a frost on them, after March 1 20%, and after March 8 10%. The 28 days between the even-odds date and the one-in-ten date is wider than at 89% 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 6 in half of years, as early as November 17 one year in ten, and holds off past January 6 one year in ten. A hard freeze of 28°F follows 19 days later, around December 25; in spring the one-in-ten date for 28°F is February 28, 8 days before the 32°F one. The freeze-free season lasts 302 days in a typical year, longer than at 89% of the 339 Texas stations; it reaches 341 days one year in ten and falls short of 268 one year in ten. On average 9 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 20 days longer, to about February 28, and return around November 24. A 24°F night is unusual: 40% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 2 | Feb 12 | Feb 18 | Feb 24 | Feb 28 | Mar 3 | Mar 8 | Mar 13 | Mar 24 |
| 32°F99% of yrs | Jan 1 | Jan 19 | Jan 27 | Feb 1 | Feb 8 | Feb 15 | Feb 22 | Mar 1 | Mar 8 |
| 28°F78% of yrs | Dec 16 | Dec 29 | Jan 6 | Jan 15 | Jan 23 | Jan 31 | Feb 4 | Feb 13 | Feb 28 |
| 24°F40% 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 12 | Nov 17 | Nov 20 | Nov 24 | Nov 29 | Dec 2 | Dec 7 | Dec 14 |
| 32°F99% of yrs | Nov 17 | Nov 22 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 18 | Dec 28 | Jan 6 |
| 28°F78% of yrs | Nov 28 | Dec 4 | Dec 10 | Dec 18 | Dec 25 | Jan 1 | Jan 6 | Jan 17 | Feb 1 |
| 24°F40% 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 Choke Canyon Dam, 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 78071 →Compare Three Rivers with another place →
Weather by month in Three Rivers
August is the warmest month at Choke Canyon Dam, TX, averaging 97°F by day and 74°F at night; January is the coldest at 64°F and 43°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 50% of years and March still brings one in 21% of years.
Warmth for growing adds up to 7,702 growing degree days a year (base 50°F), more than at 83% of the 351 Texas stations. 43% of them (3,324) have built up by the end of June, and August adds the most, 1,096. Precipitation totals 26.6 inches a year, most in September (3.6") and least in February (1.4"); May to September bring 52% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 64 | 43 | 1.5 | 73% | 4 | 177 |
| Feb | 68 | 47 | 1.4 | 50% | 2 | 247 |
| Mar | 75 | 53 | 2.4 | 21% | 1 | 449 |
| Apr | 81 | 59 | 2.0 | 0% | 0 | 610 |
| May | 88 | 67 | 3.0 | 0% | 0 | 854 |
| Jun | 93 | 73 | 2.7 | 0% | 0 | 987 |
| Jul | 95 | 74 | 2.8 | 0% | 0 | 1071 |
| Aug | 97 | 74 | 1.7 | 0% | 0 | 1096 |
| Sep | 91 | 70 | 3.6 | 0% | 0 | 911 |
| Oct | 84 | 62 | 2.3 | 0% | 0 | 701 |
| Nov | 73 | 52 | 1.5 | 34% | 1 | 393 |
| Dec | 65 | 45 | 1.7 | 71% | 3 | 207 |
Monthly normals 1991–2020 at Choke Canyon Dam, TX (230 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, Beeville 5 NE, TX, 29 miles east of Three Rivers, has a last frost 9 days later (February 17), a first frost 2 days later (December 8), a season 3 days shorter.
When it snows in Three Rivers, Texas
Measurable snow is rare here: only 2 of 24 winters from 1991 to 2020 recorded 0.1 inch or more at Choke Canyon Dam, TX, 4.9 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 78071
| When | What to do |
|---|---|
| November 30 – December 14 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 14 – December 28 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 11 – January 25 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 8 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 6 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 78071 is 5 miles from Choke Canyon Dam, TX, which stands at 230 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 78022 (George West). The 2023 USDA Plant Hardiness Zone Map lists ZIP 78071 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.