Alturas, CA 96115 Frost Dates
Frost dates for Alturas, CA, ZIP 96115
Around 05/15 is the usual last spring frost, about 260 days away. The first fall frost typically arrives around 10/01, about 137 frost-free days later.
Alturas sits in USDA Zone 6b (-5 to 0°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 6b around Alturas has about 5 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
The actual range around Alturas's last frost
05/15 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 06/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Alturas compares
Alturas's growing season runs about 137 days, ranking 37,518 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,447 of 2,555.
Learn more
zone vs. frost date explains why Zone 6b and Alturas's frost date answer different questions, and the frost range explains how to read the range around Alturas's dates instead of trusting one.