USDA Hardiness Zone 9b
Frost Dates for 92278 — Twentynine Palms, California
NOAA 1991–2020 normals from Yucca Mesa, CA (3,445 ft), 15 miles southwest.
Updated
In Twentynine Palms, the last spring frost (32°F) is around February 16 in half of years and has passed by March 24 in nine years out of ten. The first fall frost comes around December 10, as early as November 23 one year in ten, leaving a typical freeze-free season of 296 days (NOAA, Yucca Mesa, CA).
- Last spring frost
- February 16
- First fall frost
- December 10
- Growing season
- 296 days
- Hardiness zone
- 9b
50% probability
50% probability
freeze-free, 50%
25 to 30°F (-3.9 to -1.1°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 5%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
1 of 20 observed
NOAA normal
Frost risk by date in Twentynine Palms
Half of springs at Yucca Mesa, CA see their last 32°F night by February 16; only one in ten is past it by December 25, and one in ten still has one after March 24. Planting tender crops after March 5 leaves a 30% risk of a frost on them, after March 14 20%, and after March 24 10%. The 36 days between the even-odds date and the one-in-ten date is wider than at 75% of the 220 California 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 23 one year in ten, and holds off past December 26 one year in ten. A hard freeze of 28°F follows 14 days later, around December 24; in spring the one-in-ten date for 28°F is March 4, 20 days before the 32°F one. The freeze-free season lasts 296 days in a typical year, longer than at 63% of the 219 California stations; it reaches 347 days one year in ten and falls short of 253 one year in ten. On average 15 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 31 days longer, to about March 19, and return around November 30. A 24°F night is unusual: 17% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 6 | Feb 27 | Mar 7 | Mar 13 | Mar 19 | Mar 26 | Mar 30 | Apr 5 | Apr 14 |
| 32°F98% of yrs | Dec 25 | Jan 4 | Jan 17 | Feb 3 | Feb 16 | Feb 25 | Mar 5 | Mar 14 | Mar 24 |
| 28°F69% of yrs | Dec 13 | Dec 23 | Dec 29 | Jan 3 | Jan 12 | Jan 29 | Feb 7 | Feb 18 | Mar 4 |
| 24°F17% of yrs | too rare for a date | ||||||||
| 20°F1% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 10 | Nov 18 | Nov 23 | Nov 27 | Nov 30 | Dec 3 | Dec 6 | Dec 9 | Dec 13 |
| 32°F98% of yrs | Nov 23 | Nov 29 | Dec 3 | Dec 7 | Dec 10 | Dec 13 | Dec 16 | Dec 21 | Dec 26 |
| 28°F69% of yrs | Dec 2 | Dec 10 | Dec 14 | Dec 19 | Dec 24 | Dec 28 | Jan 1 | Jan 14 | Feb 6 |
| 24°F17% of yrs | too rare for a date | ||||||||
| 20°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Yucca Mesa, CA, 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 92278 →Compare Twentynine Palms with another place →
Weather by month in Twentynine Palms
July is the warmest month at Yucca Mesa, CA, averaging 96°F by day and 70°F at night; December is the coldest at 58°F and 38°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 41% of years and March still brings one in 32% of years.
Warmth for growing adds up to 5,822 growing degree days a year (base 50°F), more than at 86% of the 283 California stations. 37% of them (2,145) have built up by the end of June, and July adds the most, 1,035.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 58 | 42 | 57% | 3 | 84 |
| Feb | 61 | 42 | 41% | 5 | 117 |
| Mar | 68 | 44 | 32% | 1 | 209 |
| Apr | 73 | 49 | 5% | <1 | 340 |
| May | 82 | 55 | 0% | 0 | 571 |
| Jun | 92 | 63 | 0% | 0 | 825 |
| Jul | 96 | 70 | 0% | 0 | 1035 |
| Aug | 96 | 70 | 0% | 0 | 1021 |
| Sep | 89 | 64 | 0% | 0 | 799 |
| Oct | 80 | 55 | 0% | <1 | 545 |
| Nov | 67 | 45 | 23% | 1 | 214 |
| Dec | 58 | 38 | 88% | 5 | 61 |
Monthly normals 1991–2020 at Yucca Mesa, CA (3,445 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, Joshua Tree, CA, 15 miles south of Twentynine Palms and 882 feet lower, has a last frost 12 days later (February 28), a first frost 9 days earlier (December 1), a season 23 days shorter.
When it snows in Twentynine Palms, California
Measurable snow is rare here: only 1 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Twentynine Palms, CA, 18.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 92278
| 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 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 92278 is 15 miles from Yucca Mesa, CA, which stands at 3,445 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 92278 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across California →
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.