When is the last frost in Larkspur, CA?

For ZIP code 94939, the average last spring frost (32°F) is January 16, based on NOAA 1991-2020 climate normals for the Kentfield, CA weather station. There is a 1-in-10 chance of a frost after February 25.

When is the first frost in Larkspur, CA?

The average first fall frost (32°F) is December 18. There is a 1-in-10 chance of frost by November 30, so tender plants are at risk from that point on.

How long is the growing season in 94939?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 334 days long.

Are these frost dates a forecast?

No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.

Frost dates for 94939Larkspur, CA

The average last spring frost in Larkspur is January 16 and the average first fall frost is December 18, giving a typical growing season of about 334 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jan 16
Average first fall frost: Dec 18
Growing season: 334 days

Frost risk by date

NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.

Spring dates: chance of a frost AFTER the date. Fall dates: chance of a frost BEFORE the date.
Temperature	Last spring: 90% / 50% / 10% chance	First fall: 10% / 50% / 90% chance	Growing season (50%)	Years with at least one
Light frost (36°F)	Jan 29 · Mar 5 · Apr 5	Nov 12 · Nov 29 · Dec 21	265 days	100%
Frost / freeze (32°F)	Dec 21 · Jan 16 · Feb 25	Nov 30 · Dec 18 · Jan 19	334 days	86%
Hard freeze (28°F)	Dec 9 · Dec 30 · Jan 23	Dec 4 · Dec 24 · Jan 21	365 days	27%

Where these dates come from

ZIP code 94939 is matched to the NOAA station Kentfield, CA, 2.3 km away, at 145 ft elevation (93 ft higher than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Kentfield, CA (used)	145 ft	Jan 16	Dec 18
San Rafael Civic Ctr, CA	120 ft	Jan 11	Dec 21
Richmond, CA	20 ft	Jan 4	Jan 2
San Francisco Dwtn, CA	150 ft	—	—

Frost dates near Larkspur

Larkspur, CA 94977 · last Jan 16, first Dec 18
Greenbrae, CA 94904 · last Jan 16, first Dec 18
Corte Madera, CA 94976 · last Jan 16, first Dec 18
Kentfield, CA 94914 · last Jan 16, first Dec 18
Ross, CA 94957 · last Jan 16, first Dec 18
Mill Valley, CA 94942 · last Jan 16, first Dec 18
San Rafael, CA 94912 · last Jan 11, first Dec 21
San Quentin, CA 94974 · last Jan 4, first Jan 2

Frequently asked questions

When is the last frost in Larkspur, CA?: For ZIP code 94939, the average last spring frost (32°F) is January 16, based on NOAA 1991-2020 climate normals for the Kentfield, CA weather station. There is a 1-in-10 chance of a frost after February 25.
When is the first frost in Larkspur, CA?: The average first fall frost (32°F) is December 18. There is a 1-in-10 chance of frost by November 30, so tender plants are at risk from that point on.
How long is the growing season in 94939?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 334 days long.
Are these frost dates a forecast?: No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.