Frost Dates for Mill Valley, CA 94941

Last spring frost February 1 · First fall frost January 2 · 335 frost-free days · USDA Zone 10a

Frost probability for 94941

Frost10%50%90%
Spring (last frost)March 15February 1—
Fall (first frost)November 19January 2—

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (6.0 km away); the 50% date is the median year.

Month by month in Mill Valley

MonthWhat to do
JanuaryPlant cool-season crops: lettuce, spinach, broccoli, peas, and carrots.
FebruaryDirect sow brassicas and root vegetables. Start warm-season seedlings indoors.
MarchTransplant warm-season crops outdoors. Sow beans, cucumbers, and squash.
AprilMain warm-season planting window. Direct sow melons and sweet corn.
MaySuccession plant lettuce. Keep beds irrigated as temperatures climb.
JuneMonitor for heat stress. Harvest zucchini and cucumbers frequently.
JulyHarvest regularly to encourage continued production. Watch for pests.
AugustStart fall cool-season crops: broccoli, kale, beets, and carrots.
SeptemberPlant fall lettuce, spinach, arugula, and radishes.
OctoberHarvest mature crops. Direct sow cold-tolerant greens.
NovemberPlant garlic and onion sets. Harvest cool-season crops through the month.
DecemberPlant cool-season crops for winter harvest. Plan next year's garden.

What grows in a 335-day season

Frequently Asked Questions

What is the last frost date for Mill Valley, CA (ZIP 94941)?

The median last spring frost date for Mill Valley, CA (ZIP code 94941) is around February 1. 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 Mill Valley, CA?

The median first fall frost date for Mill Valley, CA is around January 2. 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 Mill Valley, CA?

The frost-free growing season in Mill Valley is about 335 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 Mill Valley, CA?

Based on frost date patterns, Mill Valley 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 Mill Valley, CA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around February 1). For Mill Valley, that's roughly December 7 to December 21. Transplant outdoors 1–2 weeks after your last frost.

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