USDA Hardiness Zone 9a
Frost Dates for 78118 — Karnes City, Texas
NOAA 1991–2020 normals from Karnes City 2N, TX (450 ft), 2 miles northeast.
Updated
In Karnes City, the last spring frost (32°F) is around February 16 in half of years and has passed by March 13 in nine years out of ten. The first fall frost comes around December 9, as early as November 20 one year in ten, leaving a typical freeze-free season of 300 days (NOAA, Karnes City 2N, TX).
- Last spring frost
- February 16
- First fall frost
- December 9
- Growing season
- 300 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
- 7%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
1 of 15 observed
NOAA normal
Frost risk by date in Karnes City
Half of springs at Karnes City 2N, TX see their last 32°F night by February 16; only one in ten is past it by January 13, and one in ten still has one after March 13. Planting tender crops after February 28 leaves a 30% risk of a frost on them, after March 5 20%, and after March 13 10%. The 25 days between the even-odds date and the one-in-ten date is wider than at 82% 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 9 in half of years, as early as November 20 one year in ten, and holds off past January 10 one year in ten. A hard freeze of 28°F follows 18 days later, around December 27; in spring the one-in-ten date for 28°F is March 2, 11 days before the 32°F one. The freeze-free season lasts 300 days in a typical year, longer than at 87% of the 339 Texas stations; it reaches 338 days one year in ten and falls short of 264 one year in ten. On average 11 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 16 days longer, to about March 4, and return around November 27. A 24°F night is unusual: 35% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 6 | Feb 17 | Feb 24 | Feb 28 | Mar 4 | Mar 8 | Mar 13 | Mar 18 | Mar 28 |
| 32°F97% of yrs | Jan 13 | Jan 25 | Jan 31 | Feb 7 | Feb 16 | Feb 23 | Feb 28 | Mar 5 | Mar 13 |
| 28°F78% of yrs | Dec 19 | Jan 1 | Jan 12 | Jan 20 | Jan 28 | Feb 2 | Feb 9 | Feb 20 | Mar 2 |
| 24°F35% of yrs | too rare for a date | ||||||||
| 20°F9% of yrs | too rare for a date | ||||||||
| 16°F1% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 7 | Nov 13 | Nov 18 | Nov 23 | Nov 27 | Nov 30 | Dec 3 | Dec 8 | Dec 16 |
| 32°F97% of yrs | Nov 20 | Nov 27 | Dec 1 | Dec 5 | Dec 9 | Dec 15 | Dec 22 | Jan 1 | Jan 10 |
| 28°F78% of yrs | Dec 1 | Dec 6 | Dec 12 | Dec 19 | Dec 27 | Jan 2 | Jan 8 | Jan 19 | Feb 3 |
| 24°F35% of yrs | too rare for a date | ||||||||
| 20°F9% of yrs | too rare for a date | ||||||||
| 16°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Karnes City 2N, 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 78118 →Compare Karnes City with another place →
Weather by month in Karnes City
August is the warmest month at Karnes City 2N, TX, averaging 97°F by day and 73°F at night; January is the coldest at 65°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 56% of years and March still brings one in 29% of years.
Warmth for growing adds up to 7,588 growing degree days a year (base 50°F), more than at 79% of the 351 Texas stations. 43% of them (3,256) have built up by the end of June, and August adds the most, 1,088.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 65 | 43 | 76% | 4 | 187 |
| Feb | 68 | 46 | 56% | 2 | 232 |
| Mar | 74 | 52 | 29% | <1 | 418 |
| Apr | 82 | 59 | 0% | 0 | 605 |
| May | 88 | 66 | 0% | 0 | 835 |
| Jun | 93 | 72 | 0% | 0 | 979 |
| Jul | 96 | 74 | 0% | 0 | 1076 |
| Aug | 97 | 73 | 0% | 0 | 1088 |
| Sep | 91 | 69 | 0% | 0 | 898 |
| Oct | 83 | 60 | 0% | <1 | 671 |
| Nov | 74 | 51 | 27% | 1 | 390 |
| Dec | 66 | 44 | 69% | 4 | 210 |
Monthly normals 1991–2020 at Karnes City 2N, TX (450 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, Floresville, TX, 23 miles northwest of Karnes City, has a last frost 18 days later (March 6), a first frost 19 days earlier (November 20), a season 39 days shorter.
When it snows in Karnes City, Texas
Measurable snow is rare here: only 1 of 15 winters from 1991 to 2020 recorded 0.1 inch or more at Karnes City 2N, TX, 1.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 78118
| When | What to do |
|---|---|
| December 8 – December 22 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 22 – January 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 19 – February 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 16 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 25 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 9 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 78118 is 2 miles from Karnes City 2N, TX, which stands at 450 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 78119 (Kenedy). The 2023 USDA Plant Hardiness Zone Map lists ZIP 78118 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.