USDA Hardiness Zone 9b
Frost Dates for 93270 — Terra Bella, California
NOAA 1991–2020 normals from Porterville, CA (393 ft), 8 miles north.
Updated
In Terra Bella, the last spring frost (32°F) is around January 20 in half of years and has passed by February 22 in nine years out of ten. The first fall frost comes around December 13, as early as November 26 one year in ten, leaving a typical freeze-free season of 330 days (NOAA, Porterville, CA).
- Last spring frost
- January 20
- First fall frost
- December 13
- Growing season
- 330 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 Terra Bella
Half of springs at Porterville, CA see their last 32°F night by January 20; only one in ten is past it by December 25, and one in ten still has one after February 22. Planting tender crops after January 31 leaves a 30% risk of a frost on them, after February 6 20%, and after February 22 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 13 in half of years, as early as November 26 one year in ten, and holds off past January 6 one year in ten. A hard freeze of 28°F is less common: it came in 48% of winters. The freeze-free season lasts 330 days in a typical year, longer than at 82% of the 219 California stations; it reaches 361 days one year in ten and falls short of 289 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 37 days longer, to about February 26, and return around November 28. A 24°F night is unusual: 11% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 25 | Feb 3 | Feb 10 | Feb 19 | Feb 26 | Mar 6 | Mar 16 | Mar 30 | Apr 7 |
| 32°F91% of yrs | Dec 25 | Jan 1 | Jan 7 | Jan 14 | Jan 20 | Jan 26 | Jan 31 | Feb 6 | Feb 22 |
| 28°F48% of yrs | too rare for a date | ||||||||
| 24°F11% 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 17 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 3 | Dec 7 | Dec 14 |
| 32°F91% of yrs | Nov 26 | Dec 1 | Dec 5 | Dec 9 | Dec 13 | Dec 16 | Dec 21 | Dec 28 | Jan 6 |
| 28°F48% of yrs | too rare for a date | ||||||||
| 24°F11% of yrs | too rare for a date | ||||||||
| 20°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Porterville, 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 93270 →Compare Terra Bella with another place →
Weather by month in Terra Bella
July is the warmest month at Porterville, CA, averaging 98°F by day and 68°F at night; December is the coldest at 59°F and 39°F. From March to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 23% of years.
Warmth for growing adds up to 5,946 growing degree days a year (base 50°F), more than at 89% of the 283 California stations. 39% of them (2,300) have built up by the end of June, and July adds the most, 1,035. Precipitation totals 11.1 inches a year, most in January (2.1") and least in August (0.0"); May to September bring 5% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 59 | 40 | 2.1 | 66% | 6 | 63 |
| Feb | 65 | 43 | 1.9 | 23% | 2 | 124 |
| Mar | 71 | 47 | 2.0 | 3% | <1 | 272 |
| Apr | 76 | 50 | 1.0 | 3% | <1 | 387 |
| May | 84 | 56 | 0.3 | 0% | 0 | 626 |
| Jun | 93 | 63 | 0.1 | 0% | 0 | 828 |
| Jul | 98 | 68 | 0.1 | 0% | 0 | 1035 |
| Aug | 97 | 67 | 0.0 | 0% | 0 | 989 |
| Sep | 92 | 62 | 0.1 | 0% | 0 | 819 |
| Oct | 82 | 53 | 0.6 | 0% | 0 | 549 |
| Nov | 68 | 44 | 1.0 | 17% | 1 | 204 |
| Dec | 59 | 39 | 1.9 | 72% | 7 | 51 |
Monthly normals 1991–2020 at Porterville, CA (393 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, Lindsay, CA, 18 miles north of Terra Bella, has a last frost 31 days later (February 20), a first frost 13 days earlier (November 30), a season 46 days shorter.
When it snows in Terra Bella, California
Measurable snow is rare here: only 1 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Lindsay, CA, 17.6 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 93270
| When | What to do |
|---|---|
| November 11 – November 25 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| November 25 – December 9 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| December 23 – January 6 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| January 20 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 20 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 29 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 13 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 93270 is 8 miles from Porterville, CA, which stands at 393 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 93257 (Porterville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 93270 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.