Frost dates for 95446Guerneville, CA
The average last spring frost in Guerneville is March 2 and the average first fall frost is November 20, giving a typical growing season of about 262 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 2
- Average first fall frost
- Nov 20
- Growing season
- 262 days
Safer after Apr 2 (1-in-10 risk)
Possible by Nov 1 (1-in-10 risk)
First frost typically in 20 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 12 · May 1 | Oct 16 · Nov 3 · Nov 21 | 206 days | 100% |
| Frost / freeze (32°F) | Jan 27 · Mar 2 · Apr 2 | Nov 1 · Nov 20 · Dec 10 | 262 days | 100% |
| Hard freeze (28°F) | Dec 20 · Jan 23 · Feb 23 | Nov 15 · Dec 5 · Jan 7 | 321 days | 91% |
Planting calendar for Guerneville
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 | Jan 30 – Apr 7 |
| Tomatoes | Transplant outdoors | Mar 18 – Jul 31 |
| Peppers | Start seeds indoors | Jan 30 – Mar 2 |
| Peppers | Transplant outdoors | Apr 1 – May 2 |
| Eggplant | Start seeds indoors | Feb 16 – Mar 17 |
| Eggplant | Transplant outdoors | Apr 1 – May 2 |
| Cucumbers | Sow outdoors | Apr 1 – Aug 10 |
| Summer squash | Sow outdoors | Mar 18 – May 2 |
| Winter squash & pumpkins | Sow outdoors | Apr 1 – May 2 |
| Snap beans | Sow outdoors | Mar 18 – Sep 2 |
| Sweet corn | Sow outdoors | Mar 18 – Jul 31 |
| Watermelon & cantaloupe | Sow outdoors | Apr 1 – May 2 |
| Okra | Sow outdoors | Mar 25 – Apr 17 |
| Peas | Sow outdoors (spring) | Jan 30 – Mar 17 |
| Potatoes | Plant outdoors (spring) | Jan 30 – Apr 1 |
| Onions | Start seeds indoors (spring) | Dec 19 – Jan 15 |
| Onions | Transplant outdoors (spring) | Feb 16 – Mar 17 |
| Broccoli | Start seeds indoors (spring) | Jan 12 – Feb 15 |
| Broccoli | Transplant outdoors (spring) | Feb 16 – Mar 17 |
| Broccoli | Start seeds indoors (fall) | Jul 21 – Jul 31 |
| Broccoli | Transplant outdoors (fall) | Aug 20 – Aug 31 |
| Cabbage | Start seeds indoors (spring) | Jan 2 – Jan 30 |
| Cabbage | Transplant outdoors (spring) | Jan 30 – Mar 2 |
| Cabbage | Start seeds indoors (fall) | Jul 11 – Aug 10 |
| Cabbage | Transplant outdoors (fall) | Aug 10 – Sep 10 |
| Leaf lettuce | Sow outdoors (spring) | Jan 30 – Apr 17 |
| Leaf lettuce | Sow outdoors (fall) | Aug 10 – Sep 26 |
| Spinach | Sow outdoors (spring) | Jan 23 – Mar 8 |
| Spinach | Sow outdoors (fall) | Aug 27 – Oct 1 |
| Radishes | Sow outdoors (spring) | Jan 30 – Mar 22 |
| Radishes | Sow outdoors (fall) | Aug 10 – Oct 11 |
| Kale | Sow outdoors (spring) | Feb 16 – Mar 8 |
| Kale | Sow outdoors (fall) | Aug 3 – Sep 10 |
| Carrots | Sow outdoors (spring) | Mar 2 – Apr 17 |
| Carrots | Sow outdoors (fall) | Jul 11 – Aug 26 |
| Garlic | Plant outdoors (fall) | Nov 10 – Dec 11 |
Where these dates come from
ZIP code 95446 is matched to the NOAA station Santa Rosa Sonoma Co Ap, CA, 16.2 km away, at 114 ft elevation (21 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Santa Rosa Sonoma Co Ap, CA (used) | 114 ft | Mar 2 | Nov 20 |
| Occidental, CA | 865 ft | Jan 29 | Dec 30 |
| Graton, CA | 200 ft | Mar 20 | Nov 13 |
| Healdsburg, CA | 177 ft | Feb 15 | Dec 2 |
Frost dates near Guerneville
- Rio Nido, CA 95471 · last Mar 2, first Nov 20
- Villa Grande, CA 95486 · last Mar 20, first Nov 13
- Monte Rio, CA 95462 · last Mar 20, first Nov 13
- Duncans Mills, CA 95430 · last Feb 26, first Dec 27
- Forestville, CA 95436 · last Mar 20, first Nov 13
- Camp Meeker, CA 95419 · last Mar 20, first Nov 13
- Occidental, CA 95465 · last Jan 29, first Dec 30
- Graton, CA 95444 · last Mar 20, first Nov 13
Frequently asked questions
- When is the last frost in Guerneville, CA?
- For ZIP code 95446, the average last spring frost (32°F) is March 2, based on NOAA 1991-2020 climate normals for the Santa Rosa Sonoma Co Ap, CA weather station. There is a 1-in-10 chance of a frost after April 2.
- When is the first frost in Guerneville, CA?
- The average first fall frost (32°F) is November 20. There is a 1-in-10 chance of frost by November 1, so tender plants are at risk from that point on.
- How long is the growing season in 95446?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 262 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.