USDA Hardiness Zone 9b
Frost Dates for 93444 — Nipomo, California
NOAA 1991–2020 normals from Santa Maria Public Airport, CA (242 ft), 10 miles south.
Updated
In Nipomo, the last spring frost (32°F) is around February 4 in half of years and has passed by March 16 in nine years out of ten. The first fall frost comes around December 13, as early as November 21 one year in ten, leaving a typical freeze-free season of 315 days (NOAA, Santa Maria Public Airport, CA).
- Last spring frost
- February 4
- First fall frost
- December 13
- Growing season
- 315 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 19 observed
NOAA normal
Frost risk by date in Nipomo
Half of springs at Santa Maria Public Airport, CA see their last 32°F night by February 4; only one in ten is past it by December 29, and one in ten still has one after March 16. Planting tender crops after February 18 leaves a 30% risk of a frost on them, after February 27 20%, and after March 16 10%. The 40 days between the even-odds date and the one-in-ten date is wider than at 85% 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 21 one year in ten, and holds off past January 10 one year in ten. A hard freeze of 28°F is less common: it came in 48% of winters. The freeze-free season lasts 315 days in a typical year, longer than at 72% of the 219 California stations; it reaches 354 days one year in ten and falls short of 268 one year in ten. On average 9 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 46 days longer, to about March 22, and return around November 25. A 24°F night is unusual: 9% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 12 | Feb 23 | Mar 2 | Mar 12 | Mar 22 | Mar 29 | Apr 3 | Apr 10 | Apr 17 |
| 32°F94% of yrs | Dec 29 | Jan 8 | Jan 19 | Jan 28 | Feb 4 | Feb 11 | Feb 18 | Feb 27 | Mar 16 |
| 28°F48% of yrs | too rare for a date | ||||||||
| 24°F9% 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 3 | Nov 11 | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 14 |
| 32°F94% of yrs | Nov 21 | Nov 30 | Dec 5 | Dec 9 | Dec 13 | Dec 18 | Dec 23 | Dec 31 | Jan 10 |
| 28°F48% of yrs | too rare for a date | ||||||||
| 24°F9% of yrs | too rare for a date | ||||||||
| 20°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Santa Maria Public 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 93444 →Compare Nipomo with another place →
Weather by month in Nipomo
August is the warmest month at Santa Maria Public Airport, CA, averaging 74°F by day and 55°F at night; December is the coldest at 64°F and 40°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 44% of years and March still brings one in 13% of years.
Warmth for growing adds up to 3,257 growing degree days a year (base 50°F), fewer than at 78% of the 283 California stations. 38% of them (1,242) have built up by the end of June, and August adds the most, 448. Precipitation totals 13.4 inches a year, most in February (2.9") and least in July (0.0"); May to September bring 4% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 65 | 41 | 2.7 | 61% | 3 | 115 |
| Feb | 65 | 43 | 2.9 | 44% | 2 | 122 |
| Mar | 66 | 44 | 2.6 | 13% | <1 | 175 |
| Apr | 68 | 45 | 0.9 | 4% | <1 | 207 |
| May | 69 | 49 | 0.4 | 0% | 0 | 279 |
| Jun | 71 | 52 | 0.1 | 0% | 0 | 344 |
| Jul | 73 | 55 | 0.0 | 0% | 0 | 437 |
| Aug | 74 | 55 | 0.0 | 0% | 0 | 448 |
| Sep | 75 | 54 | 0.1 | 0% | 0 | 431 |
| Oct | 75 | 50 | 0.5 | 0% | 0 | 378 |
| Nov | 70 | 44 | 1.1 | 19% | 1 | 221 |
| Dec | 64 | 40 | 2.1 | 72% | 4 | 100 |
Monthly normals 1991–2020 at Santa Maria Public Airport, CA (242 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, Twitchell Dam, CA, 10 miles east of Nipomo and 340 feet higher, has the same 50% last-frost date, a first frost 9 days earlier (December 4), a season 14 days shorter.
When it snows in Nipomo, California
Measurable snow is rare here: only 0 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at San Luis Obispo Poly, CA, 21.1 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 93444
| When | What to do |
|---|---|
| November 26 – December 10 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 10 – December 24 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 7 – January 21 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 4 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 93444 is 10 miles from Santa Maria Public Airport, CA, which stands at 242 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 93458 (Santa Maria). The 2023 USDA Plant Hardiness Zone Map lists ZIP 93444 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.