Frost Dates for Newbury Park, CA 91320

Last spring frost January 22 · First fall frost November 29 · 311 frost-free days · USDA Zone 10a

Frost probability for 91320

Frost10%50%90%
Spring (last frost)April 9January 22February 2
Fall (first frost)November 7November 29January 20

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (23.0 km away); the 50% date is the median year.

Month by month in Newbury Park

MonthWhat to do
JanuaryLast frost around January 22. 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 311-day season

Frequently Asked Questions

What is the last frost date for Newbury Park, CA (ZIP 91320)?

The median last spring frost date for Newbury Park, CA (ZIP code 91320) is around January 22. 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 Newbury Park, CA?

The median first fall frost date for Newbury Park, 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 Newbury Park, CA?

The frost-free growing season in Newbury Park is about 311 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 Newbury Park, CA?

Based on frost date patterns, Newbury Park 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 Newbury Park, CA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around January 22). For Newbury Park, that's roughly November 27 to December 11. Transplant outdoors 1–2 weeks after your last frost.

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