USDA Hardiness Zone 8b
Frost Dates for 78840 — Del Rio, Texas
NOAA 1991–2020 normals from Del Rio 4NW, TX (1,051 ft), 3 miles west.
Updated
In Del Rio, the last spring frost (32°F) is around February 19 in half of years and has passed by March 11 in nine years out of ten. The first fall frost comes around December 4, as early as November 16 one year in ten, leaving a typical freeze-free season of 290 days (NOAA, Del Rio 4NW, TX).
- Last spring frost
- February 19
- First fall frost
- December 4
- Growing season
- 290 days
- Hardiness zone
- 8b
50% probability
50% probability
freeze-free, 50%
15 to 20°F (-9.4 to -6.7°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 13%
- Snow per year
- 0.2"
median, 1991–2020
median, 1991–2020
2 of 16 observed
NOAA normal
Frost risk by date in Del Rio
Half of springs at Del Rio 4NW, TX see their last 32°F night by February 19; only one in ten is past it by January 24, and one in ten still has one after March 11. Planting tender crops after February 28 leaves a 30% risk of a frost on them, after March 4 20%, and after March 11 10%. The 20 days between the even-odds date and the one-in-ten date is narrower than at 51% of the 339 Texas stations behind this site's ZIP pages.
In fall the first 32°F night comes by December 4 in half of years, as early as November 16 one year in ten, and holds off past December 20 one year in ten. A hard freeze of 28°F follows 15 days later, around December 19; in spring the one-in-ten date for 28°F is March 1, 10 days before the 32°F one. The freeze-free season lasts 290 days in a typical year, longer than at 83% of the 339 Texas stations; it reaches 320 days one year in ten and falls short of 260 one year in ten. On average 21 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 13 days longer, to about March 4, and return around November 23. Nights of 24°F, cold enough to damage hardier plants, come in 56% of winters and 16°F in 2%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 13 | Feb 20 | Feb 25 | Mar 1 | Mar 4 | Mar 8 | Mar 12 | Mar 16 | Mar 25 |
| 32°F | Jan 24 | Feb 4 | Feb 10 | Feb 15 | Feb 19 | Feb 24 | Feb 28 | Mar 4 | Mar 11 |
| 28°F95% of yrs | Dec 25 | Jan 6 | Jan 16 | Jan 23 | Jan 31 | Feb 5 | Feb 11 | Feb 19 | Mar 1 |
| 24°F56% of yrs | Dec 11 | Dec 22 | Dec 29 | Jan 2 | Jan 7 | Jan 16 | Jan 25 | Feb 2 | Feb 10 |
| 20°F17% of yrs | too rare for a date | ||||||||
| 16°F2% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 5 | Nov 10 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 8 |
| 32°F | Nov 16 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 10 | Dec 15 | Dec 20 |
| 28°F95% of yrs | Nov 28 | Dec 5 | Dec 10 | Dec 14 | Dec 19 | Dec 23 | Dec 28 | Jan 4 | Jan 20 |
| 24°F56% of yrs | Dec 8 | Dec 14 | Dec 20 | Dec 25 | Dec 29 | Jan 2 | Jan 7 | Jan 19 | Feb 1 |
| 20°F17% of yrs | too rare for a date | ||||||||
| 16°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Del Rio 4NW, 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 78840 →Compare Del Rio with another place →
Weather by month in Del Rio
August is the warmest month at Del Rio 4NW, TX, averaging 98°F by day and 75°F at night; January is the coldest at 64°F and 39°F. A freezing night is all but certain in every month from December to January (a 90% chance or more). From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 77% of years and March still brings one in 29% of years.
Warmth for growing adds up to 7,668 growing degree days a year (base 50°F), more than at 82% of the 351 Texas stations. 44% of them (3,349) have built up by the end of June, and August adds the most, 1,137. Precipitation totals 20.9 inches a year, most in May (2.9") and least in January (0.7"); May to September bring 63% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 64 | 39 | 0.7 | 93% | 8 | 126 |
| Feb | 69 | 44 | 0.7 | 77% | 4 | 210 |
| Mar | 77 | 52 | 1.2 | 29% | 1 | 452 |
| Apr | 84 | 59 | 1.4 | 0% | 0 | 640 |
| May | 90 | 67 | 2.9 | 0% | 0 | 890 |
| Jun | 95 | 73 | 2.5 | 0% | 0 | 1032 |
| Jul | 98 | 75 | 2.0 | 0% | 0 | 1127 |
| Aug | 98 | 75 | 2.8 | 0% | 0 | 1137 |
| Sep | 92 | 69 | 2.9 | 0% | 0 | 914 |
| Oct | 83 | 60 | 2.0 | 1% | <1 | 664 |
| Nov | 73 | 50 | 1.0 | 38% | 1 | 350 |
| Dec | 64 | 40 | 0.8 | 96% | 8 | 127 |
Monthly normals 1991–2020 at Del Rio 4NW, TX (1,051 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, Brackettville, TX, 29 miles east of Del Rio, has a last frost 14 days later (March 5), a first frost 10 days earlier (November 24), a season 26 days shorter.
When it snows in Del Rio, Texas
Measurable snow is rare here: only 2 of 16 winters from 1991 to 2020 recorded 0.1 inch or more at Del Rio 4NW, TX, 2.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 78840
| When | What to do |
|---|---|
| December 11 – December 25 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 25 – January 8 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 22 – February 5 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 19 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 20 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 4 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 78840 is 3 miles from Del Rio 4NW, TX, which stands at 1,051 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 78840 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°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.