Frost dates 2026–2027

Frost dates for Rio Vista, California

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Antioch Pumping Plt #3, 14 mi away (close match).

Last spring frostJan 12
First fall frostDec 19
343 frost-free days
Last spring frostJan 121 year in 10 after Feb 1
First fall frostDec 191 year in 10 by Nov 29
Growing season343 daysbetween median 32°F dates
Hardiness zoneZone 9b25 to 30°F average extreme low

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Will it freeze in Rio Vista in the next 7 nights?

No overnight lows at or below 32°F are forecast in Rio Vista during the next 7 nights in the available NWS frost forecast.

Tonight: forecast low 47°F. Above 36°F.

NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.

No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.

Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.

Frost and freeze probabilities

Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.

These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.

Average first hard freeze in Rio Vista

Most years have no 28°F hard freeze at Antioch Pumping Plt #3, according to NOAA’s 1991–2020 Climate Normals. Check the short-term forecast above during cold snaps.

TemperatureLast spring date
90% · 50% · 10% chance of a later freeze
First fall date
10% · 50% · 90% chance of an earlier freeze
Season
36°F frost possible Jan 11 · Feb 8 · Mar 12 Nov 18 · Dec 4 · Dec 28 299 days
32°F freeze Dec 20 · Jan 12 · Feb 1 Nov 29 · Dec 19 · Jan 12 343 days
28°F hard freeze Dec 16 · Jan 2 · Jan 22 Dec 9 · Dec 29 · Jan 16 365 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00040232. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Antioch Pumping Plt #3

Average low temperature by month

Months with lows near or below freezing carry frost risk

Where these frost dates come from

The frost dates for Rio Vista, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Antioch Pumping Plt #3 (station USC00040232, elevation 60 ft), 14 mi from Rio Vista. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.

Frost dates near Rio Vista

CityDistanceLast spring frostFirst fall frost
Oakley, CA 12 mi Jan 12 Dec 19
Antioch, CA 14 mi Jan 12 Dec 19
Pittsburg, CA 16 mi Jan 12 Dec 19
Brentwood, CA 17 mi Jan 12 Dec 19
Suisun City, CA 17 mi Jan 15 Dec 14
Fairfield, CA 19 mi Jan 15 Dec 14
Vacaville, CA 19 mi Feb 18 Nov 28
Dixon, CA 20 mi Feb 10 Dec 1
Clayton, CA 21 mi Mar 8 Dec 22
Concord, CA 22 mi Jan 9 Dec 14

Frequently asked questions

When is the last frost in Rio Vista?

On average, the last spring frost (32°F) in Rio Vista is around January 12. In about 1 year in 10 it comes after February 1, and in 9 years in 10 it comes after December 20.

When is the first frost in Rio Vista?

The first fall frost (32°F) usually arrives around December 19. There’s a 10% chance of a freeze by November 29 and a 90% chance by January 12.

Can it frost in Rio Vista after the last frost date?

Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after February 8.

What growing zone is Rio Vista?

Rio Vista is in USDA Plant Hardiness Zone 9b (average annual extreme minimum temperature 25 to 30°F), based on the 2023 USDA map for ZIP code 94571. See growing zones in California.

More: all California frost dates · California growing zones · frost vs. freeze