Frost dates for 94590Vallejo, CA
The average last spring frost in Vallejo is March 5 and the average first fall frost is November 21, giving a typical growing season of about 256 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 5
- Average first fall frost
- Nov 21
- Growing season
- 256 days
Safer after Apr 16 (1-in-10 risk)
Possible by Nov 3 (1-in-10 risk)
First frost typically in 25 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.
| 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) | Mar 17 · Apr 17 · May 9 | Oct 16 · Nov 4 · Nov 22 | 199 days | 100% |
| Frost / freeze (32°F) | Jan 26 · Mar 5 · Apr 16 | Nov 3 · Nov 21 · Dec 13 | 256 days | 100% |
| Hard freeze (28°F) | Dec 20 · Jan 23 · Feb 28 | Nov 16 · Dec 5 · Jan 11 | 323 days | 92% |
Planting calendar for Vallejo
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Feb 2 – Apr 10 |
| Tomatoes | Transplant outdoors | Mar 21 – Aug 1 |
| Peppers | Start seeds indoors | Feb 2 – Mar 5 |
| Peppers | Transplant outdoors | Apr 4 – May 5 |
| Eggplant | Start seeds indoors | Feb 19 – Mar 20 |
| Eggplant | Transplant outdoors | Apr 4 – May 5 |
| Cucumbers | Sow outdoors | Apr 4 – Aug 11 |
| Summer squash | Sow outdoors | Mar 21 – May 5 |
| Winter squash & pumpkins | Sow outdoors | Apr 4 – May 5 |
| Snap beans | Sow outdoors | Mar 21 – Sep 3 |
| Sweet corn | Sow outdoors | Mar 21 – Aug 1 |
| Watermelon & cantaloupe | Sow outdoors | Apr 4 – May 5 |
| Okra | Sow outdoors | Mar 28 – Apr 20 |
| Peas | Sow outdoors (spring) | Feb 2 – Mar 20 |
| Potatoes | Plant outdoors (spring) | Feb 2 – Apr 4 |
| Onions | Start seeds indoors (spring) | Dec 22 – Jan 18 |
| Onions | Transplant outdoors (spring) | Feb 19 – Mar 20 |
| Broccoli | Start seeds indoors (spring) | Jan 15 – Feb 18 |
| Broccoli | Transplant outdoors (spring) | Feb 19 – Mar 20 |
| Broccoli | Start seeds indoors (fall) | Jul 22 – Aug 1 |
| Broccoli | Transplant outdoors (fall) | Aug 21 – Sep 1 |
| Cabbage | Start seeds indoors (spring) | Jan 5 – Feb 2 |
| Cabbage | Transplant outdoors (spring) | Feb 2 – Mar 5 |
| Cabbage | Start seeds indoors (fall) | Jul 12 – Aug 11 |
| Cabbage | Transplant outdoors (fall) | Aug 11 – Sep 11 |
| Leaf lettuce | Sow outdoors (spring) | Feb 2 – Apr 20 |
| Leaf lettuce | Sow outdoors (fall) | Aug 11 – Sep 27 |
| Spinach | Sow outdoors (spring) | Jan 26 – Mar 11 |
| Spinach | Sow outdoors (fall) | Aug 28 – Oct 2 |
| Radishes | Sow outdoors (spring) | Feb 2 – Mar 25 |
| Radishes | Sow outdoors (fall) | Aug 11 – Oct 12 |
| Kale | Sow outdoors (spring) | Feb 19 – Mar 11 |
| Kale | Sow outdoors (fall) | Aug 4 – Sep 11 |
| Carrots | Sow outdoors (spring) | Mar 5 – Apr 20 |
| Carrots | Sow outdoors (fall) | Jul 12 – Aug 27 |
| Garlic | Plant outdoors (fall) | Nov 11 – Dec 12 |
Where these dates come from
ZIP code 94590 is matched to the NOAA station Napa Co Ap, CA, 12.1 km away, at 14 ft elevation (12 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Napa Co Ap, CA (used) | 14 ft | Mar 5 | Nov 21 |
| Vallejo, CA | 341 ft | Jan 17 | Dec 27 |
| Martinez Wtp, CA | 40 ft | Feb 28 | Nov 22 |
| Napa State Hospital, CA | 35 ft | Feb 12 | Dec 4 |
Frost dates near Vallejo
- Vallejo, CA 94592 · last Mar 5, first Nov 21
- Crockett, CA 94525 · last Feb 28, first Nov 22
- American Canyon, CA 94503 · last Mar 5, first Nov 21
- Rodeo, CA 94572 · last Feb 28, first Nov 22
- Port Costa, CA 94569 · last Feb 28, first Nov 22
- Benicia, CA 94510 · last Feb 28, first Nov 22
- Hercules, CA 94547 · last Feb 28, first Nov 22
- Pinole, CA 94564 · last Jan 4, first Jan 2
Frequently asked questions
- When is the last frost in Vallejo, CA?
- For ZIP code 94590, the average last spring frost (32°F) is March 5, based on NOAA 1991-2020 climate normals for the Napa Co Ap, CA weather station. There is a 1-in-10 chance of a frost after April 16.
- When is the first frost in Vallejo, CA?
- The average first fall frost (32°F) is November 21. There is a 1-in-10 chance of frost by November 3, so tender plants are at risk from that point on.
- How long is the growing season in 94590?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 256 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.