USDA Hardiness Zone 10b
Frost Dates for 92688 — Rancho Santa Margarita, California
NOAA 1991–2020 normals from Irvine Rch, CA (540 ft), 9 miles northwest.
Updated
Frost is not a yearly event in Rancho Santa Margarita: a night at or below 32°F came in 4% of the winters of 1991–2020 at Irvine Rch, CA, and a 36°F night, cold enough for frost on exposed leaves, in 38%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 4%
- Winters with 36°F
- 38%
- Coldest month low
- 48°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 18 observed
NOAA normal
Frost risk by date in Rancho Santa Margarita
At Irvine Rch, CA, 9 miles northwest of Rancho Santa Margarita, 4% of the winters of 1991–2020 had at least one night at or below 32°F, and none reached 28°F. Even a 36°F night came in only 38% of winters. December is the month most likely to bring one: a 2% 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.
Freeze probabilities 1991–2020 at Irvine Rch, 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 92688 →Compare Rancho Santa Margarita with another place →
Weather by month in Rancho Santa Margarita
August is the warmest month at Irvine Rch, CA, averaging 90°F by day and 62°F at night; December is the coldest at 68°F and 48°F. Every month stays under a 10% chance of a 32°F night; December is the likeliest at 2%.
Warmth for growing adds up to 6,135 growing degree days a year (base 50°F), more than at 93% of the 283 California stations. 40% of them (2,474) have built up by the end of June, and August adds the most, 812. Precipitation totals 13.0 inches a year, most in February (3.5") and least in June (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 | 49 | 2.7 | 1% | <1 | 276 |
| Feb | 71 | 48 | 3.5 | 0% | <1 | 260 |
| Mar | 73 | 50 | 1.7 | 0% | 0 | 354 |
| Apr | 76 | 52 | 0.9 | 0% | 0 | 425 |
| May | 79 | 56 | 0.3 | 0% | 0 | 541 |
| Jun | 83 | 59 | 0.0 | 0% | 0 | 618 |
| Jul | 88 | 62 | 0.1 | 0% | 0 | 775 |
| Aug | 90 | 62 | 0.0 | 0% | 0 | 812 |
| Sep | 89 | 62 | 0.1 | 0% | 0 | 758 |
| Oct | 84 | 58 | 0.6 | 0% | 0 | 653 |
| Nov | 76 | 53 | 0.8 | 0% | 0 | 422 |
| Dec | 68 | 48 | 2.3 | 2% | <1 | 242 |
Monthly normals 1991–2020 at Irvine Rch, CA (540 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, Tustin Irvine Rch, CA, 10 miles northwest of Rancho Santa Margarita and 305 feet lower, has a 32°F night in 50% of winters against 4% here, and a coolest-month low 5°F colder (43°F).
When it snows in Rancho Santa Margarita, California
Measurable snow is rare here: only 0 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Laguna Beach, CA, 12.2 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 92688 is 9 miles from Irvine Rch, CA, which stands at 540 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 92692 (Mission Viejo). The 2023 USDA Plant Hardiness Zone Map lists ZIP 92688 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.