Frost Dates for Claremont, CA 91711

Last spring frost January 26 · First fall frost December 21 · 329 frost-free days · USDA Zone 10a

Frost probability for 91711

Frost10%50%90%
Spring (last frost)March 7January 26—
Fall (first frost)November 18December 21—

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (36.0 km away); the 50% date is the median year.

Month by month in Claremont

MonthWhat to do
JanuaryLast frost around January 26. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
FebruaryFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
MarchSuccession plant lettuce and greens. Keep beds weeded and watered consistently.
AprilHarvest regularly to encourage production. Monitor for pests and disease.
MayMidsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall.
JuneDirect sow carrots and beets for fall harvest. Start fall broccoli and kale indoors.
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.
OctoberDirect sow carrots and beets for fall harvest. Start fall broccoli and kale indoors.
NovemberFirst fall frost approaching (around December 21). Transplant fall brassicas. Sow spinach, arugula, and radishes.
DecemberFirst frost around December 21. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.

What grows in a 329-day season

Frequently Asked Questions

What is the last frost date for Claremont, CA (ZIP 91711)?

The median last spring frost date for Claremont, CA (ZIP code 91711) is around January 26. 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 Claremont, CA?

The median first fall frost date for Claremont, CA is around December 21. 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 Claremont, CA?

The frost-free growing season in Claremont is about 329 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 Claremont, CA?

Based on frost date patterns, Claremont falls approximately in 10a. 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 Claremont, CA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around January 26). For Claremont, that's roughly December 1 to December 15. Transplant outdoors 1–2 weeks after your last frost.

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