Frost Dates for Colton, CA 92324

Last spring frost January 21 · First fall frost December 24 · 337 frost-free days · USDA Zone 10a

Frost probability for 92324

Frost10%50%90%
Spring (last frost)March 8January 21—
Fall (first frost)November 21December 24—

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (11.7 km away); the 50% date is the median year.

Month by month in Colton

MonthWhat to do
JanuaryLast frost around January 21. 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 24). Transplant fall brassicas. Sow spinach, arugula, and radishes.
DecemberFirst frost around December 24. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.

What grows in a 337-day season

Frequently Asked Questions

What is the last frost date for Colton, CA (ZIP 92324)?

The median last spring frost date for Colton, CA (ZIP code 92324) is around January 21. 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 Colton, CA?

The median first fall frost date for Colton, CA is around December 24. 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 Colton, CA?

The frost-free growing season in Colton is about 337 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 Colton, CA?

Based on frost date patterns, Colton 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 Colton, CA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around January 21). For Colton, that's roughly November 26 to December 10. Transplant outdoors 1–2 weeks after your last frost.

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