USDA Hardiness Zone 9b
Frost Dates for 96080 — Red Bluff, California
NOAA 1991–2020 normals from Red Bluff Municipal Airport, CA (353 ft), 2 miles south.
Updated
In Red Bluff, the last spring frost (32°F) is around February 22 in half of years and has passed by March 30 in nine years out of ten. The first fall frost comes around November 29, as early as November 12 one year in ten, leaving a typical freeze-free season of 281 days (NOAA, Red Bluff Municipal Airport, CA).
- Last spring frost
- February 22
- First fall frost
- November 29
- Growing season
- 281 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
- 0"
median, 1991–2020
median, 1991–2020
0 of 25 observed
NOAA normal
Frost risk by date in Red Bluff
Half of springs at Red Bluff Municipal Airport, CA see their last 32°F night by February 22; only one in ten is past it by January 17, and one in ten still has one after March 30. Planting tender crops after March 5 leaves a 30% risk of a frost on them, after March 14 20%, and after March 30 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 November 29 in half of years, as early as November 12 one year in ten, and holds off past December 18 one year in ten. A hard freeze of 28°F follows 16 days later, around December 15; in spring the one-in-ten date for 28°F is February 21, 37 days before the 32°F one. The freeze-free season lasts 281 days in a typical year, longer than at 52% of the 219 California stations; it reaches 321 days one year in ten and falls short of 242 one year in ten. On average 19 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 36 days longer, to about March 30, and return around November 15. A 24°F night is unusual: 35% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 1 | Mar 11 | Mar 17 | Mar 24 | Mar 30 | Apr 4 | Apr 8 | Apr 12 | Apr 19 |
| 32°F | Jan 17 | Jan 31 | Feb 8 | Feb 16 | Feb 22 | Feb 28 | Mar 5 | Mar 14 | Mar 30 |
| 28°F86% of yrs | Dec 18 | Dec 25 | Dec 31 | Jan 5 | Jan 13 | Jan 20 | Jan 28 | Feb 5 | Feb 21 |
| 24°F35% of yrs | too rare for a date | ||||||||
| 20°F5% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 1 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 30 |
| 32°F | Nov 12 | Nov 18 | Nov 22 | Nov 26 | Nov 29 | Dec 1 | Dec 6 | Dec 10 | Dec 18 |
| 28°F86% of yrs | Nov 28 | Dec 2 | Dec 6 | Dec 11 | Dec 15 | Dec 19 | Dec 26 | Jan 1 | Jan 12 |
| 24°F35% of yrs | too rare for a date | ||||||||
| 20°F5% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Red Bluff Municipal Airport, 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 96080 →Compare Red Bluff with another place →
Weather by month in Red Bluff
July is the warmest month at Red Bluff Municipal Airport, CA, averaging 98°F by day and 66°F at night; December is the coldest at 56°F and 38°F. A freezing night is all but certain in December (a 90% chance or more). From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 65% of years and March still brings one in 32% of years.
Warmth for growing adds up to 5,227 growing degree days a year (base 50°F), more than at 72% of the 283 California stations. 37% of them (1,917) have built up by the end of June, and July adds the most, 992. Precipitation totals 23.2 inches a year, most in January (4.7") and least in July (0.1"); May to September bring 9% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 57 | 38 | 4.7 | 82% | 6 | 31 |
| Feb | 61 | 41 | 4.2 | 65% | 3 | 75 |
| Mar | 66 | 44 | 2.9 | 32% | 1 | 167 |
| Apr | 72 | 47 | 1.6 | 9% | <1 | 293 |
| May | 82 | 55 | 1.3 | 0% | 0 | 560 |
| Jun | 91 | 62 | 0.4 | 0% | 0 | 792 |
| Jul | 98 | 66 | 0.1 | 0% | 0 | 992 |
| Aug | 96 | 64 | 0.1 | 0% | 0 | 927 |
| Sep | 91 | 59 | 0.2 | 0% | 0 | 760 |
| Oct | 79 | 51 | 1.0 | 0% | 0 | 470 |
| Nov | 64 | 43 | 2.5 | 54% | 2 | 135 |
| Dec | 56 | 38 | 4.2 | 90% | 7 | 26 |
Monthly normals 1991–2020 at Red Bluff Municipal Airport, CA (353 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, Redding Municipal Airport, CA, 23 miles north of Red Bluff, has a last frost 9 days later (March 3), a first frost 8 days earlier (November 21), a season 20 days shorter.
When it snows in Red Bluff, California
Measurable snow is rare here: only 0 of 25 winters from 1991 to 2020 recorded 0.1 inch or more at Coleman Fisheries Stn, CA, 15.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 96080
| When | What to do |
|---|---|
| December 14 – December 28 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 28 – January 11 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 25 – February 8 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 22 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 6 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 15 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 29 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 96080 is 2 miles from Red Bluff Municipal Airport, CA, which stands at 353 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 96080 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.