Cool, CA frost dates
Last spring frostFeb 25median date
First fall frostDec 5median date
Growing season283 daysfrost-free
Hardiness zone9bZone 9b
How Cool compares
- In 8 years out of 10, the last spring frost in Cool falls between January 15 and April 7, a 82-day window. The first fall frost falls between November 15 and December 31.
- The median last frost is 34 days earlier than the California median of Mar 31.
- Its 283-day growing season is longer than 84% of the 636 California places with a regular frost season (state median 235 days).
- The last frost is 5 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 20 nights a year at or below 32°F.
- Cool shares its weather station with Rocklin, CA, 26 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | January 15 |
| 50% (median) | February 25 |
| 10% (safe for tender plants) | April 7 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 15 |
| 50% (median) | December 5 |
| 90% (late) | December 31 |
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 Cool, CA
Cool, CA frost dates — last frost Feb 25, first frost Dec 5, zone 9b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Dec 3 to Dec 17Transplant outside: Jan 28 to Feb 11
Start indoors: Dec 17 to Dec 31Transplant outside: Mar 11 to Mar 25
Start indoors: Dec 17 to Dec 31Transplant outside: Mar 11 to Mar 25
Start indoors: Dec 31 to Jan 14Start indoors: Dec 31 to Jan 14Transplant outside: Mar 4 to Mar 18
Start indoors: Dec 31 to Jan 14Start indoors: Dec 31 to Jan 14Transplant outside: Feb 4 to Feb 18Sow outdoors: Jan 28 to Mar 4Plant for fall: Oct 10 to Nov 7
Start indoors: Dec 31 to Jan 14Start indoors: Dec 31 to Jan 14Transplant outside: Jan 28 to Feb 11Sow outdoors: Jan 28 to Feb 11Plant for fall: Sep 26 to Oct 17
Start indoors: Dec 31 to Jan 14Start indoors: Dec 31 to Jan 14Transplant outside: Feb 11 to Feb 25Plant for fall: Aug 29 to Sep 19
Start indoors: Dec 31 to Jan 14Start indoors: Dec 31 to Jan 14Transplant outside: Feb 4 to Feb 18Plant for fall: Aug 29 to Sep 19
Start indoors: Dec 31 to Jan 14Start indoors: Dec 31 to Jan 14Transplant outside: Feb 11 to Feb 25Plant for fall: Aug 29 to Sep 19
Start indoors: Jan 14 to Jan 28Transplant outside: Mar 18 to Apr 1Sow outdoors: Mar 18 to Apr 1
Start indoors: Jan 14 to Jan 28Transplant outside: Mar 4 to Mar 18
Sow outdoors: Jan 14 to Feb 4Plant for fall: Sep 12 to Oct 3
Sow outdoors: Jan 14 to Feb 4Plant for fall: Oct 10 to Oct 31
Sow outdoors: Jan 21 to Mar 4Plant for fall: Oct 24 to Nov 14
Start indoors: Jan 28 to Feb 4Transplant outside: Mar 11 to Mar 18Sow outdoors: Mar 4 to Mar 18Plant for fall: Sep 19 to Oct 3
Start indoors: Jan 28 to Feb 4Sow outdoors: Mar 4 to Mar 18Plant for fall: Sep 26 to Oct 10
Start indoors: Jan 28 to Feb 4Sow outdoors: Mar 4 to Mar 18
Start indoors: Jan 28 to Feb 4Transplant outside: Mar 11 to Mar 25
Sow outdoors: Feb 4 to Mar 4Plant for fall: Sep 12 to Sep 26
Sow outdoors: Feb 4 to Mar 4Plant for fall: Sep 26 to Oct 10
Sow outdoors: Feb 4 to Feb 25
Sow outdoors: Feb 11 to Mar 11Plant for fall: Sep 26 to Oct 10
Sow outdoors: Feb 11 to Mar 4Plant for fall: Oct 10 to Oct 31
Sow outdoors: Mar 4 to Mar 25Plant for fall: Sep 19 to Oct 3
Sow outdoors: Mar 4 to Mar 18
Transplant outside: Mar 11 to Apr 1
Plant for fall: Nov 21 to Dec 26
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Cool, CA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 3 – Dec 17 | Jan 28 – Feb 11 | — | — |
| Peppers | Dec 17 – Dec 31 | Mar 11 – Mar 25 | — | — |
| Eggplant | Dec 17 – Dec 31 | Mar 11 – Mar 25 | — | — |
| Tomatoes | Dec 31 – Jan 14 | Mar 4 – Mar 18 | — | — |
| Lettuce | Dec 31 – Jan 14 | Feb 4 – Feb 18 | Jan 28 – Mar 4 | Oct 10 – Nov 7 |
| Kale | Dec 31 – Jan 14 | Jan 28 – Feb 11 | Jan 28 – Feb 11 | Sep 26 – Oct 17 |
| Broccoli | Dec 31 – Jan 14 | Feb 11 – Feb 25 | — | Aug 29 – Sep 19 |
| Cabbage | Dec 31 – Jan 14 | Feb 4 – Feb 18 | — | Aug 29 – Sep 19 |
| Cauliflower | Dec 31 – Jan 14 | Feb 11 – Feb 25 | — | Aug 29 – Sep 19 |
| Okra | Jan 14 – Jan 28 | Mar 18 – Apr 1 | Mar 18 – Apr 1 | — |
| Basil | Jan 14 – Jan 28 | Mar 4 – Mar 18 | — | — |
| Peas | — | — | Jan 14 – Feb 4 | Sep 12 – Oct 3 |
| Spinach | — | — | Jan 14 – Feb 4 | Oct 10 – Oct 31 |
| Radishes | — | — | Jan 21 – Mar 4 | Oct 24 – Nov 14 |
| Cucumbers | Jan 28 – Feb 4 | Mar 11 – Mar 18 | Mar 4 – Mar 18 | Sep 19 – Oct 3 |
| Zucchini & Summer Squash | Jan 28 – Feb 4 | — | Mar 4 – Mar 18 | Sep 26 – Oct 10 |
| Winter Squash & Pumpkins | Jan 28 – Feb 4 | — | Mar 4 – Mar 18 | — |
| Melons & Watermelon | Jan 28 – Feb 4 | Mar 11 – Mar 25 | — | — |
| Carrots | — | — | Feb 4 – Mar 4 | Sep 12 – Sep 26 |
| Beets | — | — | Feb 4 – Mar 4 | Sep 26 – Oct 10 |
| Potatoes | — | — | Feb 4 – Feb 25 | — |
| Swiss Chard | — | — | Feb 11 – Mar 11 | Sep 26 – Oct 10 |
| Cilantro | — | — | Feb 11 – Mar 4 | Oct 10 – Oct 31 |
| Green Beans | — | — | Mar 4 – Mar 25 | Sep 19 – Oct 3 |
| Sweet Corn | — | — | Mar 4 – Mar 18 | — |
| Sweet Potatoes | — | Mar 11 – Apr 1 | — | — |
| Garlic | — | — | — | Nov 21 – Dec 26 |
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 Auburn, CA weather station, 9 km away (elevation 1,293 ft (394 m)).
Frost dates near Cool
- Greenwood Apr 12 · Nov 21
- Lotus Apr 12 · Nov 21
- Auburn Feb 25 · Dec 5
- Pilot Hill Feb 25 · Dec 5
- Garden Valley Apr 12 · Nov 21
- Applegate Apr 3 · Nov 24
- Coloma Mar 31 · Nov 21
- Meadow Vista Feb 25 · Dec 5
- Newcastle Feb 25 · Dec 5
- Weimar Apr 3 · Nov 24
Frequently asked questions
When is the last frost in Cool, CA?
The median last spring frost in Cool, CA is February 25. There is still about a 10% chance of frost after April 7, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Cool, CA?
The median first fall frost is December 5, with about a 10% chance of frost before November 15.
How long is the growing season in Cool, CA?
About 283 days between the median last spring frost and first fall frost.
What planting zone is Cool, CA?
Cool, CA is in USDA hardiness zone 9b.