Palo Alto, CA Frost Dates & Growing Season

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

Last spring frost
Feb 1
~50% chance of frost after
First fall frost
Dec 7
~50% chance of frost before
Growing season
309 days
frost-free stretch
USDA zone
≈ 9b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Dec 28 Feb 1 Mar 4
First fall frost Jan 6 Dec 7 Nov 20
Hard freeze (28°F), median last Jan 4 · first Dec 22

Computed from NOAA 1991–2020 climate normals at the PALO ALTO 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 Palo Alto

Computed from Palo Alto'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 Dec 7 – Dec 21 Feb 8 – Feb 15
🫑 Peppers Nov 23 – Dec 7 Feb 15 – Feb 22
🥬 Lettuce Dec 21 – Jan 4 Jan 4 – Jan 18 Jan 4 – Feb 1
🫛 Peas Dec 21 – Jan 4
🥕 Carrots Jan 11 – Feb 1
🥦 Broccoli Dec 14 – Dec 28 Jan 11 – Jan 25
🥬 Kale Dec 21 – Jan 4 Jan 4 – Jan 18 Jan 4 – Jan 18
🥒 Cucumbers Jan 4 – Jan 11 Feb 8 – Feb 15 Feb 8 – Feb 15
🥒 Zucchini Jan 4 – Jan 11 Feb 8 – Feb 15 Feb 8 – Feb 15
🫘 Green Beans (Bush) Feb 8 – Feb 15
🌽 Sweet Corn Feb 8 – Feb 15
🌿 Basil Dec 21 – Jan 4 Feb 8 – Feb 15 Feb 15 – Feb 22
🧄 Garlic Fall: Oct 26 – Nov 23

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 Palo Alto's dates automatically after a lookup.

Reading the season in Palo Alto

With roughly 309 frost-free days, Palo Alto 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 Dec 7 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Palo Alto, CA?

The average last spring frost in Palo Alto is around Feb 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 Palo Alto, CA?

The average first fall frost in Palo Alto arrives around Dec 7. 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 Palo Alto?

About 309 frost-free days on average, from Feb 1 to Dec 7. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Palo Alto in?

USDA zone 9b 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.