When is the last frost in Rio Vista, CA?

For ZIP code 94571, the average last spring frost (32°F) is January 12, based on NOAA 1991-2020 climate normals for the Antioch Pumping Plt #3, CA weather station. There is a 1-in-10 chance of a frost after February 1.

When is the first frost in Rio Vista, CA?

The average first fall frost (32°F) is December 19. There is a 1-in-10 chance of frost by November 29, so tender plants are at risk from that point on.

How long is the growing season in 94571?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 343 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 94571Rio Vista, CA

The average last spring frost in Rio Vista is January 12 and the average first fall frost is December 19, giving a typical growing season of about 343 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jan 12
Average first fall frost: Dec 19
Growing season: 343 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 11 · Feb 8 · Mar 12	Nov 18 · Dec 4 · Dec 28	299 days	100%
Frost / freeze (32°F)	Dec 20 · Jan 12 · Feb 1	Nov 29 · Dec 19 · Jan 12	343 days	81%
Hard freeze (28°F)	Dec 16 · Jan 2 · Jan 22	Dec 9 · Dec 29 · Jan 16	365 days	35%

Where these dates come from

ZIP code 94571 is matched to the NOAA station Antioch Pumping Plt #3, CA, 20.5 km away, at 60 ft elevation (6 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Antioch Pumping Plt #3, CA (used)	60 ft	Jan 12	Dec 19
Vacaville Nut Tree Ap, CA	109 ft	Feb 18	Nov 28
Fairfield, CA	40 ft	Jan 15	Dec 14
Vacaville, CA	110 ft	Jan 31	Dec 11

Frost dates near Rio Vista

Isleton, CA 95641 · last Jan 12, first Dec 19
Birds Landing, CA 94512 · last Jan 12, first Dec 19
Ryde, CA 95680 · last Feb 9, first Dec 5
Bethel Island, CA 94511 · last Jan 12, first Dec 19
Walnut Grove, CA 95690 · last Feb 9, first Dec 5
Oakley, CA 94561 · last Jan 12, first Dec 19
Courtland, CA 95615 · last Feb 2, first Dec 2
Antioch, CA 94509 · last Jan 12, first Dec 19

Frequently asked questions

When is the last frost in Rio Vista, CA?: For ZIP code 94571, the average last spring frost (32°F) is January 12, based on NOAA 1991-2020 climate normals for the Antioch Pumping Plt #3, CA weather station. There is a 1-in-10 chance of a frost after February 1.
When is the first frost in Rio Vista, CA?: The average first fall frost (32°F) is December 19. There is a 1-in-10 chance of frost by November 29, so tender plants are at risk from that point on.
How long is the growing season in 94571?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 343 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.