USDA Hardiness Zone 8a
Frost Dates for 76943 — Ozona, Texas
NOAA 1991–2020 normals from Ozona, TX (2,345 ft), 7 miles north.
Updated
In Ozona, the last spring frost (32°F) is around March 21 in half of years and has passed by April 12 in nine years out of ten. The first fall frost comes around November 6, as early as October 24 one year in ten, leaving a typical freeze-free season of 227 days (NOAA, Ozona, TX).
- Last spring frost
- March 21
- First fall frost
- November 6
- Growing season
- 227 days
- Hardiness zone
- 8a
50% probability
50% probability
freeze-free, 50%
10 to 15°F (-12.2 to -9.4°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 8%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
2 of 25 observed
NOAA normal
Frost risk by date in Ozona
Half of springs at Ozona, TX see their last 32°F night by March 21; only one in ten is past it by March 3, and one in ten still has one after April 12. Planting tender crops after March 31 leaves a 30% risk of a frost on them, after April 5 20%, and after April 12 10%. The 22 days between the even-odds date and the one-in-ten date is wider than at 63% 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 November 6 in half of years, as early as October 24 one year in ten, and holds off past November 21 one year in ten. A hard freeze of 28°F follows 10 days later, around November 16; in spring the one-in-ten date for 28°F is March 29, 14 days before the 32°F one. The freeze-free season lasts 227 days in a typical year, shorter than at 79% of the 339 Texas stations; it reaches 250 days one year in ten and falls short of 202 one year in ten. On average 67 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 17 days longer, to about April 7, and return around October 31. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 72%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 18 | Mar 27 | Apr 1 | Apr 4 | Apr 7 | Apr 10 | Apr 14 | Apr 19 | Apr 25 |
| 32°F | Mar 3 | Mar 8 | Mar 13 | Mar 17 | Mar 21 | Mar 26 | Mar 31 | Apr 5 | Apr 12 |
| 28°F | Feb 20 | Feb 26 | Mar 2 | Mar 5 | Mar 8 | Mar 12 | Mar 16 | Mar 20 | Mar 29 |
| 24°F | Feb 3 | Feb 11 | Feb 17 | Feb 22 | Feb 26 | Mar 1 | Mar 4 | Mar 9 | Mar 15 |
| 20°F98% of yrs | Jan 7 | Jan 20 | Jan 29 | Feb 2 | Feb 7 | Feb 13 | Feb 21 | Mar 1 | Mar 6 |
| 16°F72% of yrs | Dec 9 | Dec 22 | Dec 31 | Jan 10 | Jan 19 | Jan 29 | Feb 3 | Feb 11 | Feb 25 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 17 | Oct 21 | Oct 24 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 6 | Nov 11 |
| 32°F | Oct 24 | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 8 | Nov 12 | Nov 16 | Nov 21 |
| 28°F | Nov 1 | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 19 | Nov 23 | Nov 27 | Dec 2 |
| 24°F | Nov 10 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Nov 30 | Dec 4 | Dec 9 | Dec 17 |
| 20°F98% of yrs | Nov 19 | Nov 27 | Dec 1 | Dec 4 | Dec 10 | Dec 16 | Dec 24 | Dec 31 | Jan 10 |
| 16°F72% of yrs | Nov 30 | Dec 5 | Dec 12 | Dec 20 | Dec 26 | Jan 1 | Jan 7 | Jan 20 | Feb 4 |
Freeze probabilities 1991–2020 at Ozona, 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 76943 →Compare Ozona with another place →
Weather by month in Ozona
July is the warmest month at Ozona, TX, averaging 94°F by day and 70°F at night; January is the coldest at 60°F and 30°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 29% of years.
Warmth for growing adds up to 5,933 growing degree days a year (base 50°F), fewer than at 75% of the 351 Texas stations. 42% of them (2,491) have built up by the end of June, and July adds the most, 1,003. Precipitation totals 20.0 inches a year, most in May (2.8") and least in December (0.8"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 60 | 30 | 1.0 | 100% | 20 | 36 |
| Feb | 64 | 34 | 0.9 | 100% | 13 | 82 |
| Mar | 71 | 42 | 2.0 | 92% | 6 | 246 |
| Apr | 80 | 51 | 1.8 | 29% | 1 | 462 |
| May | 87 | 61 | 2.8 | 1% | 0 | 743 |
| Jun | 93 | 69 | 2.0 | 0% | 0 | 924 |
| Jul | 94 | 70 | 1.3 | 0% | 0 | 1003 |
| Aug | 94 | 70 | 1.8 | 0% | 0 | 984 |
| Sep | 89 | 63 | 2.1 | 0% | 0 | 773 |
| Oct | 79 | 52 | 2.2 | 26% | 1 | 480 |
| Nov | 67 | 39 | 1.3 | 97% | 9 | 159 |
| Dec | 60 | 32 | 0.8 | 100% | 18 | 43 |
Monthly normals 1991–2020 at Ozona, TX (2,345 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, Sonora, TX, 35 miles east of Ozona and 207 feet lower, has a last frost 11 days later (April 1), the same first-frost date, a season 6 days shorter.
When it snows in Ozona, Texas
Measurable snow is rare here: only 2 of 25 winters from 1991 to 2020 recorded 0.1 inch or more at Acton Rch, TX, 18.5 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 76943
| When | What to do |
|---|---|
| January 10 – January 24 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 24 – February 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 21 – March 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 14 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 23 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 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 76943 is 7 miles from Ozona, TX, which stands at 2,345 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 76943 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°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.