Frost Dates for 94550 — Livermore, California

Half of springs at Livermore, CA see their last 32°F night by February 15; only one in ten is past it by January 12, and one in ten still has one after March 13. Planting tender crops after February 28 leaves a 30% risk of a frost on them, after March 5 20%, and after March 13 10%. The 26 days between the even-odds date and the one-in-ten date is narrower than at 67% 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 December 2 in half of years, as early as November 16 one year in ten, and holds off past December 28 one year in ten. A hard freeze of 28°F follows 16 days later, around December 18; in spring the one-in-ten date for 28°F is February 10, 31 days before the 32°F one. The freeze-free season lasts 292 days in a typical year, longer than at 59% of the 219 California stations; it reaches 330 days one year in ten and falls short of 257 one year in ten. On average 13 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 38 days longer, to about March 25, and return around November 18. A 24°F night is unusual: 24% of winters had one.

July is the warmest month at Livermore, CA, averaging 89°F by day and 57°F at night; December is the coldest at 57°F and 39°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 59% of years and March still brings one in 27% of years.

Warmth for growing adds up to 4,091 growing degree days a year (base 50°F), fewer than at 58% of the 283 California stations. 36% of them (1,484) have built up by the end of June, and July adds the most, 707. Precipitation totals 14.5 inches a year, most in January (2.8") and least in July (0.0"); May to September bring 5% of it.

The nearest other station, Tracy Pumping Plt, CA, 12 miles northeast of Livermore and 332 feet lower, has a last frost 27 days earlier (January 19), a first frost 8 days later (December 10), a season 38 days longer.

Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Livermore, CA, 5.2 miles away, so there is no typical first-snow date to plan around.

ZIP 94550 is 5 miles from Livermore, CA, which stands at 393 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 94568 (Dublin). The 2023 USDA Plant Hardiness Zone Map lists ZIP 94550 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.