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Will it freeze in Napa in the next 7 nights?
No overnight lows at or below 32°F are forecast in Napa during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 45°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.
- Tonight 45°F Above 36°F · Mostly Clear
- Fri, Nov 6 43°F Above 36°F · Mostly Clear
- Sat, Nov 7 44°F Above 36°F · Mostly Clear then Areas Of Fog
- Sun, Nov 8 45°F Above 36°F · Areas Of Fog
- Mon, Nov 9 45°F Above 36°F · Mostly Clear then Areas Of Fog
- Tue, Nov 10 47°F Above 36°F · Partly Cloudy then Areas Of Fog
- Wed, Nov 11 46°F Above 36°F · Chance Light Rain
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 Napa
The median first fall hard-freeze date (28°F) is December 19, from NOAA’s 1991–2020 Climate Normals at Napa State Hospital. This is the 50% probability date, not a forecast for this year.
| Temperature | Last 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 | Feb 26 · Mar 27 · Apr 19 | Oct 31 · Nov 17 · Dec 4 | 236 days |
| 32°F freeze | Jan 3 · Feb 12 · Mar 13 | Nov 15 · Dec 4 · Jan 4 | 299 days |
| 28°F hard freeze | Dec 16 · Jan 11 · Feb 13 | Dec 1 · Dec 19 · Jan 23 | 348 days |
Average high temperature by month
1991–2020 normals at Napa State Hospital
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 Napa, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Napa State Hospital (station USC00046074, elevation 35 ft), 2.4 mi from Napa. 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 Napa
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| American Canyon, CA | 8.7 mi | Mar 5 | Nov 21 |
| Sonoma, CA | 8.7 mi | Mar 2 | Nov 27 |
| Vallejo, CA | 13 mi | Jan 17 | Dec 27 |
| Fairfield, CA | 15 mi | Jan 15 | Dec 14 |
| Suisun City, CA | 16 mi | Jan 15 | Dec 14 |
| St. Helena, CA | 17 mi | Feb 3 | Dec 4 |
| Benicia, CA | 17 mi | Jan 17 | Dec 27 |
| Petaluma, CA | 18 mi | Feb 28 | Nov 25 |
| Vacaville, CA | 19 mi | Feb 18 | Nov 28 |
| Hercules, CA | 19 mi | Jan 17 | Dec 27 |
Frequently asked questions
When is the last frost in Napa?
On average, the last spring frost (32°F) in Napa is around February 12. In about 1 year in 10 it comes after March 13, and in 9 years in 10 it comes after January 3.
When is the first frost in Napa?
The first fall frost (32°F) usually arrives around December 4. There’s a 10% chance of a freeze by November 15 and a 90% chance by January 4.
Can it frost in Napa 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 March 27.
What growing zone is Napa?
Napa 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 94559. See growing zones in California.
More: all California frost dates · California growing zones · UV index today in Napa · frost vs. freeze