USDA Hardiness Zone 9b
Frost Dates for 93221 — Exeter, California
NOAA 1991–2020 normals from Lemon Cove, CA (513 ft), 7 miles northeast.
Updated
In Exeter, the last spring frost (32°F) is around February 5 in half of years and has passed by March 20 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 307 days (NOAA, Lemon Cove, CA).
- Last spring frost
- February 5
- First fall frost
- December 8
- Growing season
- 307 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 20 observed
NOAA normal
Frost risk by date in Exeter
Half of springs at Lemon Cove, CA see their last 32°F night by February 5; only one in ten is past it by January 1, and one in ten still has one after March 20. Planting tender crops after February 23 leaves a 30% risk of a frost on them, after March 3 20%, and after March 20 10%. The 43 days between the even-odds date and the one-in-ten date is wider than at 91% 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 January 8 one year in ten. A hard freeze of 28°F follows 14 days later, around December 22; in spring the one-in-ten date for 28°F is February 13, 35 days before the 32°F one. The freeze-free season lasts 307 days in a typical year, longer than at 68% of the 219 California stations; it reaches 347 days one year in ten and falls short of 262 one year in ten. On average 16 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 48 days longer, to about March 25, and return around November 23. A 24°F night is unusual: 10% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 13 | Feb 26 | Mar 5 | Mar 15 | Mar 25 | Mar 31 | Apr 4 | Apr 10 | Apr 17 |
| 32°F98% of yrs | Jan 1 | Jan 14 | Jan 23 | Jan 31 | Feb 5 | Feb 11 | Feb 23 | Mar 3 | Mar 20 |
| 28°F57% of yrs | Dec 17 | Dec 25 | Dec 30 | Jan 1 | Jan 5 | Jan 12 | Jan 18 | Jan 26 | Feb 13 |
| 24°F10% of yrs | too rare for a date | ||||||||
| 20°F0% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 7 | Nov 13 | Nov 16 | Nov 20 | Nov 23 | Nov 26 | Nov 29 | Dec 2 | Dec 8 |
| 32°F98% of yrs | Nov 23 | Nov 28 | Dec 1 | Dec 5 | Dec 8 | Dec 12 | Dec 18 | Dec 29 | Jan 8 |
| 28°F57% of yrs | Dec 5 | Dec 10 | Dec 14 | Dec 18 | Dec 22 | Dec 28 | Jan 1 | Jan 8 | Jan 20 |
| 24°F10% of yrs | too rare for a date | ||||||||
| 20°F0% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Lemon Cove, 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 93221 →Compare Exeter with another place →
Weather by month in Exeter
July is the warmest month at Lemon Cove, CA, averaging 100°F by day and 65°F at night; December is the coldest at 59°F and 37°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 43% of years and March still brings one in 20% of years.
Warmth for growing adds up to 5,719 growing degree days a year (base 50°F), more than at 84% of the 283 California stations. 39% of them (2,202) have built up by the end of June, and July adds the most, 1,007. Precipitation totals 14.1 inches a year, most in January (2.7") and least in July (0.0"); May to September bring 6% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 60 | 38 | 2.7 | 73% | 6 | 48 |
| Feb | 65 | 41 | 2.3 | 43% | 1 | 116 |
| Mar | 71 | 45 | 2.5 | 20% | <1 | 255 |
| Apr | 77 | 47 | 1.4 | 3% | <1 | 371 |
| May | 86 | 54 | 0.6 | 0% | 0 | 608 |
| Jun | 94 | 59 | 0.2 | 0% | 0 | 806 |
| Jul | 100 | 65 | 0.0 | 0% | 0 | 1007 |
| Aug | 99 | 63 | 0.0 | 0% | 0 | 967 |
| Sep | 94 | 59 | 0.1 | 0% | 0 | 789 |
| Oct | 83 | 51 | 0.7 | 0% | 0 | 526 |
| Nov | 69 | 43 | 1.3 | 25% | 1 | 189 |
| Dec | 59 | 37 | 2.3 | 74% | 7 | 39 |
Monthly normals 1991–2020 at Lemon Cove, CA (513 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, 8 miles southeast of Exeter, has a last frost 15 days later (February 20), a first frost 8 days earlier (November 30), a season 23 days shorter.
When it snows in Exeter, California
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Lemon Cove, CA, 7.2 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 93221
| When | What to do |
|---|---|
| November 27 – December 11 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 11 – December 25 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 8 – January 22 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 5 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 93221 is 7 miles from Lemon Cove, CA, which stands at 513 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 93221 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.