When is the last frost in Half Moon Bay, CA?

For ZIP code 94019, the average last spring frost (32°F) is February 6, based on NOAA 1991-2020 climate normals for the Half Moon Bay, CA weather station. There is a 1-in-10 chance of a frost after March 25.

When is the first frost in Half Moon Bay, CA?

The average first fall frost (32°F) is December 17. There is a 1-in-10 chance of frost by November 25, so tender plants are at risk from that point on.

How long is the growing season in 94019?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 328 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 94019Half Moon Bay, CA

The average last spring frost in Half Moon Bay is February 6 and the average first fall frost is December 17, giving a typical growing season of about 328 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Feb 6
Average first fall frost: Dec 17
Growing season: 328 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)	Feb 23 · Apr 3 · May 1	Oct 20 · Nov 20 · Dec 16	230 days	100%
Frost / freeze (32°F)	Dec 17 · Feb 6 · Mar 25	Nov 25 · Dec 17 · Feb 13	328 days	82%
Hard freeze (28°F)	Dec 5 · Jan 5 · Feb 26	Dec 4 · Dec 31 · Feb 23	365 days	19%

Where these dates come from

ZIP code 94019 is matched to the NOAA station Half Moon Bay, CA, 0.8 km away, at 27 ft elevation (12 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Half Moon Bay, CA (used)	27 ft	Feb 6	Dec 17
Pacifica 4 Sse, CA	475 ft	Jan 11	Jan 10
San Francisco Intl Ap, CA	8 ft	Dec 29	Dec 26
Woodside Fire Stn 1, CA	380 ft	Feb 25	Nov 25

Frost dates near Half Moon Bay

El Granada, CA 94018 · last Feb 6, first Dec 17
Moss Beach, CA 94038 · last Jan 11, first Jan 10
Montara, CA 94037 · last Feb 6, first Dec 17
Burlingame, CA 94010 · last Dec 29, first Dec 26
San Mateo, CA 94497 · last Feb 25, first Nov 25
Millbrae, CA 94030 · last Dec 29, first Dec 26
Belmont, CA 94002 · last Jan 17, first Dec 12
Redwood City, CA 94062 · last Mar 21, first Dec 15

Frequently asked questions

When is the last frost in Half Moon Bay, CA?: For ZIP code 94019, the average last spring frost (32°F) is February 6, based on NOAA 1991-2020 climate normals for the Half Moon Bay, CA weather station. There is a 1-in-10 chance of a frost after March 25.
When is the first frost in Half Moon Bay, CA?: The average first fall frost (32°F) is December 17. There is a 1-in-10 chance of frost by November 25, so tender plants are at risk from that point on.
How long is the growing season in 94019?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 328 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.