USDA Hardiness Zone 9b
Frost Dates for 95988 — Willows, California
NOAA 1991–2020 normals from Willows 6 W, CA (234 ft), 5 miles west.
Updated
In Willows, the last spring frost (32°F) is around February 21 in half of years and has passed by April 9 in nine years out of ten. The first fall frost comes around December 6, as early as November 16 one year in ten, leaving a typical freeze-free season of 289 days (NOAA, Willows 6 W, CA).
- Last spring frost
- February 21
- First fall frost
- December 6
- Growing season
- 289 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
- 0%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
0 of 30 observed
NOAA normal
Frost risk by date in Willows
Half of springs at Willows 6 W, CA see their last 32°F night by February 21; only one in ten is past it by January 4, and one in ten still has one after April 9. Planting tender crops after March 13 leaves a 30% risk of a frost on them, after March 29 20%, and after April 9 10%. The 47 days between the even-odds date and the one-in-ten date is wider than at 96% 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 6 in half of years, as early as November 16 one year in ten, and holds off past December 29 one year in ten. A hard freeze of 28°F follows 12 days later, around December 18; in spring the one-in-ten date for 28°F is February 24, 44 days before the 32°F one. The freeze-free season lasts 289 days in a typical year, longer than at 58% of the 219 California stations; it reaches 334 days one year in ten and falls short of 235 one year in ten. On average 23 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 40 days longer, to about April 2, and return around November 23. A 24°F night is unusual: 18% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 25 | Mar 10 | Mar 20 | Mar 27 | Apr 2 | Apr 7 | Apr 12 | Apr 17 | Apr 25 |
| 32°F99% of yrs | Jan 4 | Jan 15 | Jan 30 | Feb 11 | Feb 21 | Mar 1 | Mar 13 | Mar 29 | Apr 9 |
| 28°F70% of yrs | Dec 14 | Dec 21 | Dec 28 | Dec 31 | Jan 5 | Jan 14 | Jan 24 | Feb 5 | Feb 24 |
| 24°F18% 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 7 | Nov 12 | Nov 15 | Nov 20 | Nov 23 | Nov 26 | Nov 29 | Dec 2 | Dec 7 |
| 32°F99% of yrs | Nov 16 | Nov 24 | Nov 29 | Dec 2 | Dec 6 | Dec 10 | Dec 14 | Dec 18 | Dec 29 |
| 28°F70% of yrs | Nov 30 | Dec 5 | Dec 11 | Dec 15 | Dec 18 | Dec 24 | Dec 30 | Jan 6 | Jan 27 |
| 24°F18% of yrs | too rare for a date | ||||||||
| 20°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Willows 6 W, 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 95988 →Compare Willows with another place →
Weather by month in Willows
July is the warmest month at Willows 6 W, CA, averaging 95°F by day and 63°F at night; December is the coldest at 58°F and 39°F. From May to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 47% of years and March still brings one in 27% of years and April still brings one in 17% of years.
Warmth for growing adds up to 5,247 growing degree days a year (base 50°F), more than at 73% of the 283 California stations. 38% of them (2,004) have built up by the end of June, and July adds the most, 894. Precipitation totals 22.0 inches a year, most in January (4.4") 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 | 58 | 40 | 4.4 | 76% | 6 | 51 |
| Feb | 63 | 42 | 4.2 | 47% | 4 | 99 |
| Mar | 68 | 44 | 2.8 | 27% | 2 | 201 |
| Apr | 75 | 47 | 1.5 | 17% | 1 | 333 |
| May | 83 | 54 | 1.2 | 1% | <1 | 566 |
| Jun | 90 | 60 | 0.5 | 0% | 0 | 754 |
| Jul | 95 | 63 | 0.0 | 0% | 0 | 894 |
| Aug | 94 | 61 | 0.1 | 0% | 0 | 851 |
| Sep | 91 | 58 | 0.2 | 0% | 0 | 741 |
| Oct | 82 | 53 | 1.1 | 0% | 0 | 530 |
| Nov | 67 | 44 | 2.4 | 33% | 2 | 184 |
| Dec | 58 | 39 | 3.6 | 85% | 8 | 43 |
Monthly normals 1991–2020 at Willows 6 W, CA (234 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, Orland, CA, 17 miles north of Willows, has a last frost 4 days later (February 25), a first frost 4 days earlier (December 2), a season 10 days shorter.
When it snows in Willows, California
Measurable snow is rare here: only 0 of 30 winters from 1991 to 2020 recorded 0.1 inch or more at Willows 6 W, CA, 5.4 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 95988
| When | What to do |
|---|---|
| December 13 – December 27 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 27 – January 10 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 24 – February 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 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 95988 is 5 miles from Willows 6 W, CA, which stands at 234 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 95988 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.