USDA Hardiness Zone 9a
Frost Dates for 95666 — Pioneer, California
NOAA 1991–2020 normals from Pacific House, CA (3,450 ft), 17 miles north.
Updated
In Pioneer, the last spring frost (32°F) is around April 26 in half of years and has passed by May 19 in nine years out of ten. The first fall frost comes around November 2, as early as October 14 one year in ten, leaving a typical freeze-free season of 191 days (NOAA, Pacific House, CA).
- Last spring frost
- April 26
- First fall frost
- November 2
- Growing season
- 191 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
- 25%
- Snow per year
- 3.7"
median, 1991–2020
median, 1991–2020
6 of 24 observed
NOAA normal
Frost risk by date in Pioneer
Half of springs at Pacific House, CA see their last 32°F night by April 26; only one in ten is past it by April 10, and one in ten still has one after May 19. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 9 20%, and after May 19 10%. The 23 days between the even-odds date and the one-in-ten date is narrower than at 78% 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 November 2 in half of years, as early as October 14 one year in ten, and holds off past November 20 one year in ten. A hard freeze of 28°F follows 20 days later, around November 22; in spring the one-in-ten date for 28°F is April 24, 25 days before the 32°F one. The freeze-free season lasts 191 days in a typical year, shorter than at 84% of the 219 California stations; it reaches 214 days one year in ten and falls short of 162 one year in ten. On average 97 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 24 days longer, to about May 20, and return around October 16. Nights of 24°F, cold enough to damage hardier plants, come in 99% of winters and 16°F in 26%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 29 | May 3 | May 8 | May 14 | May 20 | May 26 | May 31 | Jun 3 | Jun 9 |
| 32°F | Apr 10 | Apr 16 | Apr 19 | Apr 22 | Apr 26 | Apr 29 | May 2 | May 9 | May 19 |
| 28°F | Mar 10 | Mar 22 | Mar 30 | Apr 3 | Apr 6 | Apr 9 | Apr 13 | Apr 17 | Apr 24 |
| 24°F99% of yrs | Jan 22 | Feb 8 | Feb 19 | Feb 28 | Mar 5 | Mar 11 | Mar 18 | Mar 27 | Apr 4 |
| 20°F77% of yrs | Dec 20 | Jan 2 | Jan 12 | Jan 24 | Feb 5 | Feb 13 | Feb 23 | Mar 1 | Mar 7 |
| 16°F26% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 5 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 24 | Oct 29 | Nov 4 |
| 32°F | Oct 14 | Oct 20 | Oct 24 | Oct 30 | Nov 2 | Nov 6 | Nov 10 | Nov 15 | Nov 20 |
| 28°F | Oct 31 | Nov 9 | Nov 15 | Nov 18 | Nov 22 | Nov 26 | Dec 1 | Dec 5 | Dec 11 |
| 24°F99% of yrs | Nov 19 | Nov 27 | Dec 1 | Dec 6 | Dec 10 | Dec 15 | Dec 20 | Dec 28 | Jan 12 |
| 20°F77% of yrs | Dec 4 | Dec 13 | Dec 20 | Dec 28 | Jan 1 | Jan 6 | Jan 18 | Feb 6 | Feb 21 |
| 16°F26% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Pacific House, 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 95666 →Compare Pioneer with another place →
Weather by month in Pioneer
July is the warmest month at Pacific House, CA, averaging 90°F by day and 53°F at night; December is the coldest at 43°F and 31°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 35% of years.
Warmth for growing adds up to 2,775 growing degree days a year (base 50°F), fewer than at 88% of the 283 California stations. 29% of them (796) have built up by the end of June, and July adds the most, 677. Precipitation totals 54.5 inches a year, most in January (9.6") and least in July (0.0"); May to September bring 9% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 44 | 32 | 9.6 | 99% | 19 | 0 |
| Feb | 50 | 31 | 8.8 | 100% | 17 | 6 |
| Mar | 56 | 33 | 8.8 | 99% | 15 | 28 |
| Apr | 63 | 36 | 4.9 | 97% | 9 | 80 |
| May | 72 | 42 | 3.2 | 35% | 1 | 243 |
| Jun | 82 | 47 | 0.9 | 0% | 0 | 439 |
| Jul | 90 | 53 | 0.0 | 0% | 0 | 677 |
| Aug | 89 | 53 | 0.1 | 0% | 0 | 639 |
| Sep | 83 | 49 | 0.6 | 1% | <1 | 482 |
| Oct | 66 | 41 | 2.9 | 44% | 2 | 161 |
| Nov | 51 | 35 | 5.3 | 96% | 12 | 20 |
| Dec | 43 | 31 | 9.4 | 100% | 21 | 0 |
Monthly normals 1991–2020 at Pacific House, CA (3,450 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, Calaveras Big Trees, CA, 18 miles south of Pioneer and 1,245 feet higher, has a last frost 11 days later (May 7), a first frost 5 days earlier (October 28), a season 22 days shorter.
When it snows in Pioneer, California
Measurable snow is rare here: only 6 of 24 winters from 1991 to 2020 recorded 0.1 inch or more at W Pt, CA, 12.7 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 95666
| When | What to do |
|---|---|
| February 15 – March 1 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 1 – March 15 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 29 – April 12 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 26 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 10 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 19 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 2 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 95666 is 17 miles from Pacific House, CA, which stands at 3,450 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 95726 (Pollock Pines). The 2023 USDA Plant Hardiness Zone Map lists ZIP 95666 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.
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.