Challenge, CA frost dates
Last spring frostApr 1median date
First fall frostNov 17median date
Growing season230 daysfrost-free
Hardiness zone9aZone 9a
How Challenge compares
- In 8 years out of 10, the last spring frost in Challenge falls between March 4 and April 22, a 49-day window. The first fall frost falls between October 31 and December 5.
- The median last frost is 1 day later than the California median of Mar 31.
- Its 230-day growing season is longer than 46% of the 636 California places with a regular frost season (state median 235 days).
- The last frost is 29 days later than the zone 9a median of Mar 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9a chart.
- The weather station records an average of 58 nights a year at or below 32°F.
- Compared with Yuba City, CA, 57 km away, the last frost here is 49 days later than there and the growing season is 62 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 4 |
| 50% (median) | April 1 |
| 10% (safe for tender plants) | April 22 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 31 |
| 50% (median) | November 17 |
| 90% (late) | December 5 |
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 Challenge, CA
Challenge, CA frost dates — last frost Apr 1, first frost Nov 17, zone 9a. whenisthelastfrost.com
Crop
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Start indoors: Jan 7 to Jan 21Transplant outside: Mar 4 to Mar 18
Start indoors: Jan 21 to Feb 4Transplant outside: Apr 15 to Apr 29
Start indoors: Jan 21 to Feb 4Transplant outside: Apr 15 to Apr 29
Start indoors: Feb 4 to Feb 18Transplant outside: Apr 8 to Apr 22
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 11 to Mar 25Sow outdoors: Mar 4 to Apr 8Plant for fall: Sep 22 to Oct 20
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 4 to Mar 18Sow outdoors: Mar 4 to Mar 18Plant for fall: Sep 8 to Sep 29
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 18 to Apr 1Plant for fall: Aug 11 to Sep 1
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 11 to Mar 25Plant for fall: Aug 11 to Sep 1
Start indoors: Feb 4 to Feb 18Transplant outside: Mar 18 to Apr 1Plant for fall: Aug 11 to Sep 1
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 22 to May 6Sow outdoors: Apr 22 to May 6
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 8 to Apr 22
Sow outdoors: Feb 18 to Mar 11Plant for fall: Aug 25 to Sep 15
Sow outdoors: Feb 18 to Mar 11Plant for fall: Sep 22 to Oct 13
Sow outdoors: Feb 25 to Apr 8Plant for fall: Oct 6 to Oct 27
Start indoors: Mar 4 to Mar 11Transplant outside: Apr 15 to Apr 22Sow outdoors: Apr 8 to Apr 22Plant for fall: Sep 1 to Sep 15
Start indoors: Mar 4 to Mar 11Sow outdoors: Apr 8 to Apr 22Plant for fall: Sep 8 to Sep 22
Start indoors: Mar 4 to Mar 11Sow outdoors: Apr 8 to Apr 22
Start indoors: Mar 4 to Mar 11Transplant outside: Apr 15 to Apr 29
Sow outdoors: Mar 11 to Apr 8Plant for fall: Aug 25 to Sep 8
Sow outdoors: Mar 11 to Apr 8Plant for fall: Sep 8 to Sep 22
Sow outdoors: Mar 11 to Apr 1
Sow outdoors: Mar 18 to Apr 15Plant for fall: Sep 8 to Sep 22
Sow outdoors: Mar 18 to Apr 8Plant for fall: Sep 22 to Oct 13
Sow outdoors: Apr 8 to Apr 29Plant for fall: Sep 1 to Sep 15
Sow outdoors: Apr 8 to Apr 22
Transplant outside: Apr 15 to May 6
Plant for fall: Nov 3 to Dec 8
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Challenge, CA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 7 – Jan 21 | Mar 4 – Mar 18 | — | — |
| Peppers | Jan 21 – Feb 4 | Apr 15 – Apr 29 | — | — |
| Eggplant | Jan 21 – Feb 4 | Apr 15 – Apr 29 | — | — |
| Tomatoes | Feb 4 – Feb 18 | Apr 8 – Apr 22 | — | — |
| Lettuce | Feb 4 – Feb 18 | Mar 11 – Mar 25 | Mar 4 – Apr 8 | Sep 22 – Oct 20 |
| Kale | Feb 4 – Feb 18 | Mar 4 – Mar 18 | Mar 4 – Mar 18 | Sep 8 – Sep 29 |
| Broccoli | Feb 4 – Feb 18 | Mar 18 – Apr 1 | — | Aug 11 – Sep 1 |
| Cabbage | Feb 4 – Feb 18 | Mar 11 – Mar 25 | — | Aug 11 – Sep 1 |
| Cauliflower | Feb 4 – Feb 18 | Mar 18 – Apr 1 | — | Aug 11 – Sep 1 |
| Okra | Feb 18 – Mar 4 | Apr 22 – May 6 | Apr 22 – May 6 | — |
| Basil | Feb 18 – Mar 4 | Apr 8 – Apr 22 | — | — |
| Peas | — | — | Feb 18 – Mar 11 | Aug 25 – Sep 15 |
| Spinach | — | — | Feb 18 – Mar 11 | Sep 22 – Oct 13 |
| Radishes | — | — | Feb 25 – Apr 8 | Oct 6 – Oct 27 |
| Cucumbers | Mar 4 – Mar 11 | Apr 15 – Apr 22 | Apr 8 – Apr 22 | Sep 1 – Sep 15 |
| Zucchini & Summer Squash | Mar 4 – Mar 11 | — | Apr 8 – Apr 22 | Sep 8 – Sep 22 |
| Winter Squash & Pumpkins | Mar 4 – Mar 11 | — | Apr 8 – Apr 22 | — |
| Melons & Watermelon | Mar 4 – Mar 11 | Apr 15 – Apr 29 | — | — |
| Carrots | — | — | Mar 11 – Apr 8 | Aug 25 – Sep 8 |
| Beets | — | — | Mar 11 – Apr 8 | Sep 8 – Sep 22 |
| Potatoes | — | — | Mar 11 – Apr 1 | — |
| Swiss Chard | — | — | Mar 18 – Apr 15 | Sep 8 – Sep 22 |
| Cilantro | — | — | Mar 18 – Apr 8 | Sep 22 – Oct 13 |
| Green Beans | — | — | Apr 8 – Apr 29 | Sep 1 – Sep 15 |
| Sweet Corn | — | — | Apr 8 – Apr 22 | — |
| Sweet Potatoes | — | Apr 15 – May 6 | — | — |
| Garlic | — | — | — | Nov 3 – Dec 8 |
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 Dobbins 1 S, CA weather station, 12 km away (elevation 1,640 ft (500 m)).
Frost dates near Challenge
- Brownsville Apr 1 · Nov 17
- Forbestown May 4 · Oct 30
- Clipper Mills May 4 · Oct 30
- Dobbins Apr 1 · Nov 17
- Rackerby Apr 1 · Nov 17
- Camptonville May 4 · Oct 30
- North San Juan Apr 1 · Nov 17
- Oregon House Apr 1 · Nov 17
- Feather Falls May 4 · Oct 30
- Bangor Apr 1 · Nov 17
Frequently asked questions
When is the last frost in Challenge, CA?
The median last spring frost in Challenge, CA is April 1. There is still about a 10% chance of frost after April 22, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Challenge, CA?
The median first fall frost is November 17, with about a 10% chance of frost before October 31.
How long is the growing season in Challenge, CA?
About 230 days between the median last spring frost and first fall frost.
What planting zone is Challenge, CA?
Challenge, CA is in USDA hardiness zone 9a.