USDA Hardiness Zone 10b
Frost Dates for 91913 — Chula Vista, California
NOAA 1991–2020 normals from San Diego Brown Field, CA (515 ft), 5 miles south.
Updated
Frost is not a yearly event in Chula Vista: a night at or below 32°F came in 25% of the winters of 1991–2020 at San Diego Brown Field, CA, and a 36°F night, cold enough for frost on exposed leaves, in 91%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 25%
- Winters with 36°F
- 91%
- Coldest month low
- 44°F
- Hardiness zone
- 10b
32°F or below, 1991–2020
frost possible on leaves
average, December
35 to 40°F (1.7 to 4.4°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 Chula Vista
At San Diego Brown Field, CA, 5 miles south of Chula Vista, 25% of the winters of 1991–2020 had at least one night at or below 32°F, 1% reached 28°F. Nights of 36°F, enough for frost on exposed leaves, are more common (91% of winters) and, when they come, fall between about December 20 and February 2. December is the month most likely to bring one: a 13% 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°F91% of yrs | Dec 29 | Jan 7 | Jan 18 | Jan 27 | Feb 2 | Feb 8 | Feb 17 | Feb 24 | Mar 7 |
| 32°F25% of yrs | too rare for a date | ||||||||
| 28°F1% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F91% of yrs | Dec 1 | Dec 7 | Dec 12 | Dec 16 | Dec 20 | Dec 25 | Dec 31 | Jan 7 | Jan 25 |
| 32°F25% of yrs | too rare for a date | ||||||||
| 28°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at San Diego Brown Field, 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 91913 →Compare Chula Vista with another place →
Weather by month in Chula Vista
August is the warmest month at San Diego Brown Field, CA, averaging 81°F by day and 63°F at night; December is the coldest at 67°F and 44°F. From February to November the chance of a 32°F night stays under 10% each month.
Warmth for growing adds up to 4,638 growing degree days a year (base 50°F), more than at 52% of the 283 California stations. 38% of them (1,762) have built up by the end of June, and August adds the most, 676. Precipitation totals 10.1 inches a year, most in February (2.4") 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 | 67 | 44 | 1.8 | 12% | <1 | 186 |
| Feb | 66 | 45 | 2.4 | 4% | <1 | 169 |
| Mar | 68 | 47 | 1.5 | 0% | 0 | 231 |
| Apr | 70 | 50 | 0.8 | 0% | 0 | 297 |
| May | 71 | 54 | 0.3 | 0% | 0 | 397 |
| Jun | 74 | 58 | 0.1 | 0% | 0 | 483 |
| Jul | 78 | 62 | 0.0 | 0% | 0 | 617 |
| Aug | 81 | 63 | 0.0 | 0% | 0 | 676 |
| Sep | 80 | 61 | 0.2 | 0% | 0 | 609 |
| Oct | 77 | 55 | 0.4 | 0% | 0 | 496 |
| Nov | 72 | 49 | 0.8 | 1% | 0 | 307 |
| Dec | 67 | 44 | 1.8 | 13% | <1 | 171 |
Monthly normals 1991–2020 at San Diego Brown Field, CA (515 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, Chula Vista, CA, 6 miles west of Chula Vista and 459 feet lower, has a 32°F night in 7% of winters against 25% here, and a coolest-month low 2°F warmer (46°F).
When it snows in Chula Vista, California
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Chula Vista, CA, 5.6 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 91913 is 5 miles from San Diego Brown Field, CA, which stands at 515 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 91913 in zone 10b, the band where the coldest night of the year averaged 35 to 40°F (1.7 to 4.4°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.