USDA Hardiness Zone 10a
Frost Dates for 92833 — Fullerton, California
NOAA 1991–2020 normals from Fullerton Municipal Airport, CA (96 ft), under a mile west.
Updated
Frost is not a yearly event in Fullerton: a night at or below 32°F came in 7% of the winters of 1991–2020 at Fullerton Municipal Airport, CA, and a 36°F night, cold enough for frost on exposed leaves, in 63%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 7%
- Winters with 36°F
- 63%
- Coldest month low
- 46°F
- Hardiness zone
- 10a
32°F or below, 1991–2020
frost possible on leaves
average, December
30 to 35°F (-1.1 to 1.7°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 Fullerton
At Fullerton Municipal Airport, CA, in Fullerton, 7% of the winters of 1991–2020 had at least one night at or below 32°F, and none reached 28°F. Nights of 36°F, enough for frost on exposed leaves, are more common (63% of winters) and, when they come, fall between about December 24 and January 4. December is the month most likely to bring one: a 5% chance in a given year. 62 of the 283 other California stations behind this site's ZIP pages freeze in fewer than half of winters too.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F63% of yrs | Dec 13 | Dec 19 | Dec 25 | Dec 31 | Jan 4 | Jan 8 | Jan 15 | Jan 25 | Feb 8 |
| 32°F7% of yrs | too rare for a date | ||||||||
| 28°F0% of yrs | never in 1991–2020 | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F63% of yrs | Dec 7 | Dec 12 | Dec 16 | Dec 19 | Dec 24 | Dec 27 | Jan 1 | Jan 7 | Jan 20 |
| 32°F7% of yrs | too rare for a date | ||||||||
| 28°F0% of yrs | never in 1991–2020 | ||||||||
Freeze probabilities 1991–2020 at Fullerton 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 92833 →Compare Fullerton with another place →
Weather by month in Fullerton
August is the warmest month at Fullerton Municipal Airport, CA, averaging 87°F by day and 66°F at night; December is the coldest at 68°F and 46°F. Every month stays under a 10% chance of a 32°F night; December is the likeliest at 5%.
Warmth for growing adds up to 5,940 growing degree days a year (base 50°F), more than at 88% of the 283 California stations. 40% of them (2,400) have built up by the end of June, and August adds the most, 823. Precipitation totals 11.8 inches a year, most in February (3.0") 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 | 69 | 46 | 2.9 | 3% | <1 | 239 |
| Feb | 69 | 48 | 3.0 | 0% | 0 | 244 |
| Mar | 71 | 52 | 1.7 | 0% | 0 | 349 |
| Apr | 74 | 54 | 0.6 | 0% | 0 | 420 |
| May | 76 | 58 | 0.3 | 0% | 0 | 524 |
| Jun | 79 | 63 | 0.1 | 0% | 0 | 624 |
| Jul | 84 | 66 | 0.0 | 0% | 0 | 783 |
| Aug | 87 | 66 | 0.0 | 0% | 0 | 823 |
| Sep | 85 | 65 | 0.1 | 0% | 0 | 750 |
| Oct | 80 | 58 | 0.5 | 0% | 0 | 598 |
| Nov | 74 | 51 | 0.7 | 0% | 0 | 371 |
| Dec | 68 | 46 | 1.9 | 5% | <1 | 216 |
Monthly normals 1991–2020 at Fullerton Municipal Airport, CA (96 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, Anaheim, CA, 7 miles east of Fullerton, has a 32°F night in 1% of winters against 7% here, and a coolest-month low 2°F warmer (48°F).
When it snows in Fullerton, California
Measurable snow is rare here: only 0 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Anaheim, CA, 7 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 92833 is under a mile from Fullerton Municipal Airport, CA, which stands at 96 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 22 other ZIP codes share the station; its figures are presented in full for 90650 (Norwalk). The 2023 USDA Plant Hardiness Zone Map lists ZIP 92833 in zone 10a, the band where the coldest night of the year averaged 30 to 35°F (-1.1 to 1.7°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.