Alturas Municipal Airport, CA Frost Dates & Growing Season

The two dates every Alturas Municipal Airport garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Jun 3
~50% chance of frost after
First fall frost
Sep 12
~50% chance of frost before
Growing season
101 days
frost-free stretch
USDA zone
≈ 6b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 14 Jun 3 Jun 24
First fall frost Sep 27 Sep 12 Aug 27
Hard freeze (28°F), median last May 11 · first Sep 25

Computed from NOAA 1991–2020 climate normals at the ALTURAS MUNI AP station. "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Alturas Municipal Airport

Computed from Alturas Municipal Airport's own frost dates. Click any crop for the full zone-6 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Apr 8 – Apr 22 Jun 10 – Jun 17
🫑 Peppers Mar 25 – Apr 8 Jun 17 – Jun 24
🥬 Lettuce Apr 22 – May 6 May 6 – May 20 May 6 – Jun 3
🫛 Peas Apr 22 – May 6
🥕 Carrots May 13 – Jun 3
🥦 Broccoli Apr 15 – Apr 29 May 13 – May 27
🥬 Kale Apr 22 – May 6 May 6 – May 20 May 6 – May 20
🥒 Cucumbers May 6 – May 13 Jun 10 – Jun 17 Jun 10 – Jun 17
🥒 Zucchini May 6 – May 13 Jun 10 – Jun 17 Jun 10 – Jun 17
🫘 Green Beans (Bush) Jun 10 – Jun 17
🌽 Sweet Corn Jun 10 – Jun 17
🌿 Basil Apr 22 – May 6 Jun 10 – Jun 17 Jun 17 – Jun 24
🧄 Garlic Fall: Aug 1 – Aug 29

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Alturas Municipal Airport's dates automatically after a lookup.

Reading the season in Alturas Municipal Airport

At about 101 frost-free days, Alturas Municipal Airport rewards efficiency: start warm-season crops indoors, favor short-season varieties, and lean on cold-tolerant crops — peas, kale, roots — that shrug off the shoulder-season frosts on either end.

Frequently asked questions

When is the last frost in Alturas Municipal Airport, CA?

The average last spring frost in Alturas Municipal Airport is around Jun 3, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Alturas Municipal Airport, CA?

The average first fall frost in Alturas Municipal Airport arrives around Sep 12. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Alturas Municipal Airport?

About 101 frost-free days on average, from Jun 3 to Sep 12. That favors short-season varieties and transplants for warm-season crops, with cool-season vegetables doing the heavy lifting in spring and fall.

What USDA zone is Alturas Municipal Airport in?

USDA zone 6b on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.