Frost Dates for Lathrop, CA 95330

Last spring frost February 16 · First fall frost November 30 · 287 frost-free days · USDA Zone 9b

Frost probability for 95330

Frost10%50%90%
Spring (last frost)March 19February 16January 15
Fall (first frost)November 3November 30December 17

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (14.7 km away); the 50% date is the median year.

Month by month in Lathrop

MonthWhat to do
JanuaryStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
FebruaryLast frost around February 16. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
MarchFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
AprilSuccession plant lettuce and greens. Keep beds weeded and watered consistently.
MayHarvest regularly to encourage production. Monitor for pests and disease.
JuneMidsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall.
JulyDirect sow carrots and beets for fall harvest. Start fall broccoli and kale indoors.
AugustDirect sow carrots and beets for fall harvest. Start fall broccoli and kale indoors.
SeptemberDirect sow carrots and beets for fall harvest. Start fall broccoli and kale indoors.
OctoberFirst fall frost approaching (around November 30). Transplant fall brassicas. Sow spinach, arugula, and radishes.
NovemberFirst frost around November 30. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
DecemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.

What grows in a 287-day season

Frequently Asked Questions

What is the last frost date for Lathrop, CA (ZIP 95330)?

The median last spring frost date for Lathrop, CA (ZIP code 95330) is around February 16. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Lathrop, CA?

The median first fall frost date for Lathrop, CA is around November 30. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Lathrop, CA?

The frost-free growing season in Lathrop is about 287 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Lathrop, CA?

Based on frost date patterns, Lathrop falls approximately in 9b. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Lathrop, CA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around February 16). For Lathrop, that's roughly December 22 to January 5. Transplant outdoors 1–2 weeks after your last frost.

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