Frost Dates for 92036 — Julian, California

Half of springs at Cuyamaca, CA see their last 32°F night by April 19; only one in ten is past it by March 24, and one in ten still has one after May 14. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 3 20%, and after May 14 10%. The 25 days between the even-odds date and the one-in-ten date is narrower than at 70% 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 October 27 in half of years, as early as October 9 one year in ten, and holds off past November 13 one year in ten. A hard freeze of 28°F follows 16 days later, around November 12; in spring the one-in-ten date for 28°F is April 13, 31 days before the 32°F one. The freeze-free season lasts 190 days in a typical year, shorter than at 84% of the 219 California stations; it reaches 224 days one year in ten and falls short of 156 one year in ten. On average 87 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 24 days longer, to about May 13, and return around October 12. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 30%.

August is the warmest month at Cuyamaca, CA, averaging 84°F by day and 58°F at night; December is the coldest at 51°F and 32°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 78% of years and May still brings one in 21% of years.

Warmth for growing adds up to 2,729 growing degree days a year (base 50°F), fewer than at 88% of the 283 California stations. 27% of them (745) have built up by the end of June, and August adds the most, 646. Precipitation totals 30.4 inches a year, most in February (6.4") and least in June (0.2"); May to September bring 9% of it.

The nearest other station, Mt Laguna #3, CA, 13 miles southeast of Julian and 1,280 feet higher, has a last frost 3 days later (April 22), a first frost 12 days later (November 8), a season 7 days longer.

The first measurable snow (0.1 inch or more) in Julian usually arrives around December 16, and the last of the season around March 29. Those are the middle dates across the winters of 1991–2020 at Cuyamaca, CA, 4.2 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 21 days after the last snow.

ZIP 92036 is 4 miles from Cuyamaca, CA, which stands at 4,640 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 92036 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.