Johnson Valley, CA Frost Dates & Growing Season

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

Last spring frost
Mar 1
~50% chance of frost after
First fall frost
Nov 29
~50% chance of frost before
Growing season
273 days
frost-free stretch
USDA zone
≈ 9a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Jan 24 Mar 1 Mar 29
First fall frost Dec 14 Nov 29 Nov 11
Hard freeze (28°F), median last Jan 30 · first Dec 10

Computed from NOAA 1991–2020 climate normals at the JOHNSON VALLEY 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 Johnson Valley

Computed from Johnson Valley's own frost dates. Click any crop for the full zone-9 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Jan 4 – Jan 18 Mar 8 – Mar 15
🫑 Peppers Dec 21 – Jan 4 Mar 15 – Mar 22
🥬 Lettuce Jan 18 – Feb 1 Feb 1 – Feb 15 Feb 1 – Mar 1
🫛 Peas Jan 18 – Feb 1
🥕 Carrots Feb 8 – Mar 1
🥦 Broccoli Jan 11 – Jan 25 Feb 8 – Feb 22
🥬 Kale Jan 18 – Feb 1 Feb 1 – Feb 15 Feb 1 – Feb 15
🥒 Cucumbers Feb 1 – Feb 8 Mar 8 – Mar 15 Mar 8 – Mar 15
🥒 Zucchini Feb 1 – Feb 8 Mar 8 – Mar 15 Mar 8 – Mar 15
🫘 Green Beans (Bush) Mar 8 – Mar 15
🌽 Sweet Corn Mar 8 – Mar 15
🌿 Basil Jan 18 – Feb 1 Mar 8 – Mar 15 Mar 15 – Mar 22
🧄 Garlic Fall: Oct 18 – Nov 15

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 Johnson Valley's dates automatically after a lookup.

Reading the season in Johnson Valley

With roughly 273 frost-free days, Johnson Valley gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Nov 29 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Johnson Valley, CA?

The average last spring frost in Johnson Valley is around Mar 1, 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 Johnson Valley, CA?

The average first fall frost in Johnson Valley arrives around Nov 29. 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 Johnson Valley?

About 273 frost-free days on average, from Mar 1 to Nov 29. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Johnson Valley in?

USDA zone 9a 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.