USDA Hardiness Zone 9b
Frost Dates for 93261 — Richgrove, California
NOAA 1991–2020 normals from Delano, CA (302 ft), 8 miles west.
Updated
In Richgrove, the last spring frost (32°F) is around January 31 in half of years and has passed by March 5 in nine years out of ten. The first fall frost comes around December 8, as early as November 23 one year in ten, leaving a typical freeze-free season of 309 days (NOAA, Delano, CA).
- Last spring frost
- January 31
- First fall frost
- December 8
- Growing season
- 309 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
- 0.2"
median, 1991–2020
median, 1991–2020
1 of 20 observed
NOAA normal
Frost risk by date in Richgrove
Half of springs at Delano, CA see their last 32°F night by January 31; only one in ten is past it by December 30, and one in ten still has one after March 5. Planting tender crops after February 13 leaves a 30% risk of a frost on them, after February 22 20%, and after March 5 10%. The 33 days between the even-odds date and the one-in-ten date is wider than at 61% 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 8 in half of years, as early as November 23 one year in ten, and holds off past December 30 one year in ten. A hard freeze of 28°F follows 11 days later, around December 19; in spring the one-in-ten date for 28°F is January 30, 34 days before the 32°F one. The freeze-free season lasts 309 days in a typical year, longer than at 68% of the 219 California stations; it reaches 341 days one year in ten and falls short of 273 one year in ten. On average 18 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 33 days longer, to about March 5, and return around November 24. 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 15 | Feb 22 | Feb 28 | Mar 5 | Mar 10 | Mar 16 | Mar 26 | Apr 4 |
| 32°F98% of yrs | Dec 30 | Jan 7 | Jan 15 | Jan 24 | Jan 31 | Feb 6 | Feb 13 | Feb 22 | Mar 5 |
| 28°F67% of yrs | Dec 13 | Dec 20 | Dec 25 | Dec 30 | Dec 31 | Jan 5 | Jan 10 | Jan 18 | Jan 30 |
| 24°F17% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 10 | Nov 15 | Nov 18 | Nov 21 | Nov 24 | Nov 26 | Nov 29 | Dec 3 | Dec 8 |
| 32°F98% of yrs | Nov 23 | Nov 28 | Dec 1 | Dec 4 | Dec 8 | Dec 11 | Dec 15 | Dec 21 | Dec 30 |
| 28°F67% of yrs | Dec 3 | Dec 8 | Dec 12 | Dec 15 | Dec 19 | Dec 23 | Dec 28 | Dec 31 | Jan 9 |
| 24°F17% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Delano, 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 93261 →Compare Richgrove with another place →
Compared with the next station
The nearest other station, Porterville, CA, 19 miles north of Richgrove, has a last frost 11 days earlier (January 20), a first frost 5 days later (December 13), a season 21 days longer.
When it snows in Richgrove, California
Measurable snow is rare here: only 1 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Delano, CA, 8.3 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 93261
| When | What to do |
|---|---|
| November 22 – December 6 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 6 – December 20 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 3 – January 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| January 31 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 15 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 24 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 8 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 93261 is 8 miles from Delano, CA, which stands at 302 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 93215 (Delano). The 2023 USDA Plant Hardiness Zone Map lists ZIP 93261 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.