Frost Dates for Chatsworth, CA 91311

Last spring frost January 21 · First fall frost November 29 · 312 frost-free days · USDA Zone 10a

Frost probability for 91311

Frost10%50%90%
Spring (last frost)March 17January 21—
Fall (first frost)November 7November 29—

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (26.5 km away); the 50% date is the median year.

Month by month in Chatsworth

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.
OctoberFirst fall frost approaching (around November 29). Transplant fall brassicas. Sow spinach, arugula, and radishes.
NovemberFirst frost around November 29. 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 312-day season

Frequently Asked Questions

What is the last frost date for Chatsworth, CA (ZIP 91311)?

The median last spring frost date for Chatsworth, CA (ZIP code 91311) 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 Chatsworth, CA?

The median first fall frost date for Chatsworth, CA is around November 29. 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 Chatsworth, CA?

The frost-free growing season in Chatsworth is about 312 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 Chatsworth, CA?

Based on frost date patterns, Chatsworth 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 Chatsworth, CA?

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

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