Frost Dates for 96067 — Mount Shasta, California

Half of springs at Mt Shasta, CA see their last 32°F night by May 15; only one in ten is past it by April 29, and one in ten still has one after June 5. Planting tender crops after May 23 leaves a 30% risk of a frost on them, after May 30 20%, and after June 5 10%. The 21 days between the even-odds date and the one-in-ten date is narrower than at 84% 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 6 in half of years, as early as September 20 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 19 days later, around October 25; in spring the one-in-ten date for 28°F is May 14, 22 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, shorter than at 93% of the 219 California stations; it reaches 167 days one year in ten and falls short of 115 one year in ten. On average 134 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 22 days longer, to about June 6, and return around September 19. Severe cold of 16°F or below comes in 99% of winters, usually between December 4 and February 16.

July is the warmest month at Mt Shasta, CA, averaging 85°F by day and 51°F at night; December is the coldest at 43°F and 27°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 84% of years and June still brings one in 17% of years.

Warmth for growing adds up to 2,092 growing degree days a year (base 50°F), fewer than at 93% of the 283 California stations. 27% of them (563) have built up by the end of June, and July adds the most, 561. Precipitation totals 42.5 inches a year, most in December (7.8") and least in July (0.2"); May to September bring 10% of it.

The nearest other station, Mt Shasta, CA, 1 mile northwest of Mount Shasta, has a last frost 9 days earlier (May 6), a first frost 6 days later (October 12), a season 15 days longer.

The first measurable snow (0.1 inch or more) in Mount Shasta usually arrives around November 12, and the last of the season around April 19. Those are the middle dates across the winters of 1991–2020 at Mt Shasta, CA, 0.4 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 26 days after the last snow.

ZIP 96067 is under a mile from Mt Shasta, CA, which stands at 3,613 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 96067 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°C) over 1991–2020; a zone describes winter lows, not frost dates.