Trinity River Hatchery, CA Frost Dates & Growing Season

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

Last spring frost
Apr 23
~50% chance of frost after
First fall frost
Oct 22
~50% chance of frost before
Growing season
182 days
frost-free stretch
USDA zone
≈ 8b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 3 Apr 23 May 11
First fall frost Nov 13 Oct 22 Oct 4
Hard freeze (28°F), median last Mar 28 · first Nov 6

Computed from NOAA 1991–2020 climate normals at the TRINITY RVR HATCHERY 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 Trinity River Hatchery

Computed from Trinity River Hatchery's own frost dates. Click any crop for the full zone-8 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 26 – Mar 12 Apr 30 – May 7
🫑 Peppers Feb 12 – Feb 26 May 7 – May 14
🥬 Lettuce Mar 12 – Mar 26 Mar 26 – Apr 9 Mar 26 – Apr 23
🫛 Peas Mar 12 – Mar 26
🥕 Carrots Apr 2 – Apr 23
🥦 Broccoli Mar 5 – Mar 19 Apr 2 – Apr 16
🥬 Kale Mar 12 – Mar 26 Mar 26 – Apr 9 Mar 26 – Apr 9
🥒 Cucumbers Mar 26 – Apr 2 Apr 30 – May 7 Apr 30 – May 7
🥒 Zucchini Mar 26 – Apr 2 Apr 30 – May 7 Apr 30 – May 7
🫘 Green Beans (Bush) Apr 30 – May 7
🌽 Sweet Corn Apr 30 – May 7
🌿 Basil Mar 12 – Mar 26 Apr 30 – May 7 May 7 – May 14
🧄 Garlic Fall: Sep 10 – Oct 8

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 Trinity River Hatchery's dates automatically after a lookup.

Reading the season in Trinity River Hatchery

Roughly 182 frost-free days gives Trinity River Hatchery gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 23; a fall garden sown in late summer matures comfortably before the Oct 22 frost.

Frequently asked questions

When is the last frost in Trinity River Hatchery, CA?

The average last spring frost in Trinity River Hatchery is around Apr 23, 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 Trinity River Hatchery, CA?

The average first fall frost in Trinity River Hatchery arrives around Oct 22. 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 Trinity River Hatchery?

About 182 frost-free days on average, from Apr 23 to Oct 22. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Trinity River Hatchery in?

USDA zone 8b 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.