Penngrove, CA frost dates
Last spring frostFeb 28median date
First fall frostNov 25median date
Growing season270 daysfrost-free
Hardiness zone9bZone 9b
How Penngrove compares
- In 8 years out of 10, the last spring frost in Penngrove falls between January 24 and April 6, a 72-day window. The first fall frost falls between November 9 and December 16.
- The median last frost is 31 days earlier than the California median of Mar 31.
- Its 270-day growing season is longer than 68% of the 636 California places with a regular frost season (state median 235 days).
- The last frost is 8 days later than the zone 9b median of Feb 20. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9b chart.
- The weather station records an average of 21 nights a year at or below 32°F.
- Penngrove shares its weather station with Petaluma, CA, 8 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | January 24 |
| 50% (median) | February 28 |
| 10% (safe for tender plants) | April 6 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 9 |
| 50% (median) | November 25 |
| 90% (late) | December 16 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Penngrove, CA
Penngrove, CA frost dates — last frost Feb 28, first frost Nov 25, zone 9b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Dec 6 to Dec 20Transplant outside: Jan 31 to Feb 14
Start indoors: Dec 20 to Jan 3Start indoors: Dec 20 to Jan 3Transplant outside: Mar 14 to Mar 28
Start indoors: Dec 20 to Jan 3Start indoors: Dec 20 to Jan 3Transplant outside: Mar 14 to Mar 28
Start indoors: Jan 3 to Jan 17Transplant outside: Mar 7 to Mar 21
Start indoors: Jan 3 to Jan 17Transplant outside: Feb 7 to Feb 21Sow outdoors: Jan 31 to Mar 7Plant for fall: Sep 30 to Oct 28
Start indoors: Jan 3 to Jan 17Transplant outside: Jan 31 to Feb 14Sow outdoors: Jan 31 to Feb 14Plant for fall: Sep 16 to Oct 7
Start indoors: Jan 3 to Jan 17Transplant outside: Feb 14 to Feb 28Plant for fall: Aug 19 to Sep 9
Start indoors: Jan 3 to Jan 17Transplant outside: Feb 7 to Feb 21Plant for fall: Aug 19 to Sep 9
Start indoors: Jan 3 to Jan 17Transplant outside: Feb 14 to Feb 28Plant for fall: Aug 19 to Sep 9
Start indoors: Jan 17 to Jan 31Transplant outside: Mar 21 to Apr 4Sow outdoors: Mar 21 to Apr 4
Start indoors: Jan 17 to Jan 31Transplant outside: Mar 7 to Mar 21
Sow outdoors: Jan 17 to Feb 7Plant for fall: Sep 2 to Sep 23
Sow outdoors: Jan 17 to Feb 7Plant for fall: Sep 30 to Oct 21
Sow outdoors: Jan 24 to Mar 7Plant for fall: Oct 14 to Nov 4
Start indoors: Jan 31 to Feb 7Transplant outside: Mar 14 to Mar 21Sow outdoors: Mar 7 to Mar 21Plant for fall: Sep 9 to Sep 23
Start indoors: Jan 31 to Feb 7Sow outdoors: Mar 7 to Mar 21Plant for fall: Sep 16 to Sep 30
Start indoors: Jan 31 to Feb 7Sow outdoors: Mar 7 to Mar 21
Start indoors: Jan 31 to Feb 7Transplant outside: Mar 14 to Mar 28
Sow outdoors: Feb 7 to Mar 7Plant for fall: Sep 2 to Sep 16
Sow outdoors: Feb 7 to Mar 7Plant for fall: Sep 16 to Sep 30
Sow outdoors: Feb 7 to Feb 28
Sow outdoors: Feb 14 to Mar 14Plant for fall: Sep 16 to Sep 30
Sow outdoors: Feb 14 to Mar 7Plant for fall: Sep 30 to Oct 21
Sow outdoors: Mar 7 to Mar 28Plant for fall: Sep 9 to Sep 23
Sow outdoors: Mar 7 to Mar 21
Transplant outside: Mar 14 to Apr 4
Plant for fall: Nov 11 to Dec 16
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Penngrove, CA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 6 – Dec 20 | Jan 31 – Feb 14 | — | — |
| Peppers | Dec 20 – Jan 3 | Mar 14 – Mar 28 | — | — |
| Eggplant | Dec 20 – Jan 3 | Mar 14 – Mar 28 | — | — |
| Tomatoes | Jan 3 – Jan 17 | Mar 7 – Mar 21 | — | — |
| Lettuce | Jan 3 – Jan 17 | Feb 7 – Feb 21 | Jan 31 – Mar 7 | Sep 30 – Oct 28 |
| Kale | Jan 3 – Jan 17 | Jan 31 – Feb 14 | Jan 31 – Feb 14 | Sep 16 – Oct 7 |
| Broccoli | Jan 3 – Jan 17 | Feb 14 – Feb 28 | — | Aug 19 – Sep 9 |
| Cabbage | Jan 3 – Jan 17 | Feb 7 – Feb 21 | — | Aug 19 – Sep 9 |
| Cauliflower | Jan 3 – Jan 17 | Feb 14 – Feb 28 | — | Aug 19 – Sep 9 |
| Okra | Jan 17 – Jan 31 | Mar 21 – Apr 4 | Mar 21 – Apr 4 | — |
| Basil | Jan 17 – Jan 31 | Mar 7 – Mar 21 | — | — |
| Peas | — | — | Jan 17 – Feb 7 | Sep 2 – Sep 23 |
| Spinach | — | — | Jan 17 – Feb 7 | Sep 30 – Oct 21 |
| Radishes | — | — | Jan 24 – Mar 7 | Oct 14 – Nov 4 |
| Cucumbers | Jan 31 – Feb 7 | Mar 14 – Mar 21 | Mar 7 – Mar 21 | Sep 9 – Sep 23 |
| Zucchini & Summer Squash | Jan 31 – Feb 7 | — | Mar 7 – Mar 21 | Sep 16 – Sep 30 |
| Winter Squash & Pumpkins | Jan 31 – Feb 7 | — | Mar 7 – Mar 21 | — |
| Melons & Watermelon | Jan 31 – Feb 7 | Mar 14 – Mar 28 | — | — |
| Carrots | — | — | Feb 7 – Mar 7 | Sep 2 – Sep 16 |
| Beets | — | — | Feb 7 – Mar 7 | Sep 16 – Sep 30 |
| Potatoes | — | — | Feb 7 – Feb 28 | — |
| Swiss Chard | — | — | Feb 14 – Mar 14 | Sep 16 – Sep 30 |
| Cilantro | — | — | Feb 14 – Mar 7 | Sep 30 – Oct 21 |
| Green Beans | — | — | Mar 7 – Mar 28 | Sep 9 – Sep 23 |
| Sweet Corn | — | — | Mar 7 – Mar 21 | — |
| Sweet Potatoes | — | Mar 14 – Apr 4 | — | — |
| Garlic | — | — | — | Nov 11 – Dec 16 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Petaluma Ap, CA weather station, 7 km away (elevation 20 ft (6 m)).
Frost dates near Penngrove
- Cotati Feb 28 · Nov 25
- Rohnert Park Feb 28 · Nov 25
- Petaluma Feb 28 · Nov 25
- Glen Ellen Mar 2 · Nov 27
- Eldridge Mar 2 · Nov 27
- Kenwood Feb 3 · Dec 4
- El Verano Mar 2 · Nov 27
- Boyes Hot Springs Mar 2 · Nov 27
- Santa Rosa Feb 25 · Dec 1
- Sonoma Mar 2 · Nov 27
Frequently asked questions
When is the last frost in Penngrove, CA?
The median last spring frost in Penngrove, CA is February 28. There is still about a 10% chance of frost after April 6, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Penngrove, CA?
The median first fall frost is November 25, with about a 10% chance of frost before November 9.
How long is the growing season in Penngrove, CA?
About 270 days between the median last spring frost and first fall frost.
What planting zone is Penngrove, CA?
Penngrove, CA is in USDA hardiness zone 9b.