USDA Hardiness Zone 9a
Frost Dates for 78839 — Crystal City, Texas
NOAA 1991–2020 normals from Crystal City, TX (580 ft), 1 miles southwest.
Updated
In Crystal City, the last spring frost (32°F) is around February 10 in half of years and has passed by March 9 in nine years out of ten. The first fall frost comes around December 10, as early as November 19 one year in ten, leaving a typical freeze-free season of 307 days (NOAA, Crystal City, TX).
- Last spring frost
- February 10
- First fall frost
- December 10
- Growing season
- 307 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
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 18 observed
NOAA normal
Frost risk by date in Crystal City
Half of springs at Crystal City, TX see their last 32°F night by February 10; only one in ten is past it by January 6, and one in ten still has one after March 9. Planting tender crops after February 25 leaves a 30% risk of a frost on them, after March 3 20%, and after March 9 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 10 in half of years, as early as November 19 one year in ten, and holds off past January 9 one year in ten. A hard freeze of 28°F follows 16 days later, around December 26; in spring the one-in-ten date for 28°F is February 28, 9 days before the 32°F one. The freeze-free season lasts 307 days in a typical year, longer than at 91% of the 339 Texas stations; it reaches 345 days one year in ten and falls short of 270 one year in ten. On average 8 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 28, and return around November 28. A 24°F night is unusual: 31% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 2 | Feb 12 | Feb 19 | Feb 24 | Feb 28 | Mar 4 | Mar 8 | Mar 12 | Mar 18 |
| 32°F98% of yrs | Jan 6 | Jan 21 | Jan 29 | Feb 4 | Feb 10 | Feb 18 | Feb 25 | Mar 3 | Mar 9 |
| 28°F77% of yrs | Dec 15 | Dec 28 | Jan 3 | Jan 10 | Jan 20 | Jan 29 | Feb 5 | Feb 16 | Feb 28 |
| 24°F31% 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 8 | Nov 15 | Nov 20 | Nov 24 | Nov 28 | Dec 2 | Dec 6 | Dec 11 | Dec 19 |
| 32°F98% of yrs | Nov 19 | Nov 27 | Dec 2 | Dec 6 | Dec 10 | Dec 17 | Dec 23 | Dec 31 | Jan 9 |
| 28°F77% of yrs | Dec 1 | Dec 6 | Dec 13 | Dec 19 | Dec 26 | Jan 1 | Jan 7 | Jan 20 | Feb 6 |
| 24°F31% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Crystal City, 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 78839 →Compare Crystal City with another place →
Weather by month in Crystal City
August is the warmest month at Crystal City, TX, averaging 99°F by day and 76°F at night; January is the coldest at 67°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 52% of years and March still brings one in 24% of years.
Warmth for growing adds up to 8,406 growing degree days a year (base 50°F), more than at 93% of the 351 Texas stations. 45% of them (3,758) have built up by the end of June, and August adds the most, 1,161. Precipitation totals 19.4 inches a year, most in September (2.4") and least in December (0.8"); May to September bring 55% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 67 | 44 | 1.0 | 74% | 3 | 202 |
| Feb | 72 | 49 | 0.9 | 52% | 1 | 300 |
| Mar | 79 | 55 | 1.7 | 24% | 1 | 531 |
| Apr | 86 | 62 | 1.3 | 0% | 0 | 719 |
| May | 91 | 70 | 2.2 | 0% | 0 | 941 |
| Jun | 96 | 75 | 2.1 | 0% | 0 | 1065 |
| Jul | 97 | 76 | 2.1 | 0% | 0 | 1128 |
| Aug | 99 | 76 | 1.9 | 0% | 0 | 1161 |
| Sep | 93 | 72 | 2.4 | 0% | 0 | 966 |
| Oct | 85 | 64 | 2.0 | 1% | <1 | 754 |
| Nov | 74 | 53 | 1.0 | 26% | 1 | 415 |
| Dec | 68 | 45 | 0.8 | 73% | 3 | 225 |
Monthly normals 1991–2020 at Crystal City, TX (580 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, Carrizo Springs 3S, TX, 14 miles south of Crystal City, has a last frost 23 days later (March 5), a first frost 18 days earlier (November 22), a season 42 days shorter.
When it snows in Crystal City, Texas
Measurable snow is rare here: only 0 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Crystal City, TX, 1.3 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 78839
| When | What to do |
|---|---|
| December 2 – December 16 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 16 – December 30 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 13 – January 27 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 10 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 17 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 10 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 78839 is 1 mile from Crystal City, TX, which stands at 580 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 78839 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.