Frost dates for 95945 — Grass Valley, CA
Last spring frostApr 14median date
First fall frostNov 20median date
Growing season220 daysfrost-free
Hardiness zone9aZone 9a
How Grass Valley compares
- In 8 years out of 10, the last spring frost in Grass Valley falls between March 15 and May 7, a 53-day window. The first fall frost falls between October 23 and December 12.
- The median last frost is 14 days later than the California median of Mar 31.
- Its 220-day growing season is longer than 44% of the 636 California places with a regular frost season (state median 235 days).
- The last frost is 42 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 49 nights a year at or below 32°F.
- Compared with Rocklin, CA, 50 km away, the last frost here is 48 days later than there and the growing season is 63 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 15 |
| 50% (median) | April 14 |
| 10% (safe for tender plants) | May 7 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 23 |
| 50% (median) | November 20 |
| 90% (late) | December 12 |
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 Grass Valley, CA
Frost dates for 95945 — Grass Valley, CA — last frost Apr 14, first frost Nov 20, zone 9a. whenisthelastfrost.com
Crop
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Start indoors: Jan 20 to Feb 3Transplant outside: Mar 17 to Mar 31
Start indoors: Feb 3 to Feb 17Transplant outside: Apr 28 to May 12
Start indoors: Feb 3 to Feb 17Transplant outside: Apr 28 to May 12
Start indoors: Feb 17 to Mar 3Transplant outside: Apr 21 to May 5
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 24 to Apr 7Sow outdoors: Mar 17 to Apr 21Plant for fall: Sep 25 to Oct 23
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 17 to Mar 31Sow outdoors: Mar 17 to Mar 31Plant for fall: Sep 11 to Oct 2
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 31 to Apr 14Plant for fall: Aug 14 to Sep 4
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 24 to Apr 7Plant for fall: Aug 14 to Sep 4
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 31 to Apr 14Plant for fall: Aug 14 to Sep 4
Start indoors: Mar 3 to Mar 17Transplant outside: May 5 to May 19Sow outdoors: May 5 to May 19
Start indoors: Mar 3 to Mar 17Transplant outside: Apr 21 to May 5
Sow outdoors: Mar 3 to Mar 24Plant for fall: Aug 28 to Sep 18
Sow outdoors: Mar 3 to Mar 24Plant for fall: Sep 25 to Oct 16
Sow outdoors: Mar 10 to Apr 21Plant for fall: Oct 9 to Oct 30
Start indoors: Mar 17 to Mar 24Transplant outside: Apr 28 to May 5Sow outdoors: Apr 21 to May 5Plant for fall: Sep 4 to Sep 18
Start indoors: Mar 17 to Mar 24Sow outdoors: Apr 21 to May 5Plant for fall: Sep 11 to Sep 25
Start indoors: Mar 17 to Mar 24Sow outdoors: Apr 21 to May 5
Start indoors: Mar 17 to Mar 24Transplant outside: Apr 28 to May 12
Sow outdoors: Mar 24 to Apr 21Plant for fall: Aug 28 to Sep 11
Sow outdoors: Mar 24 to Apr 21Plant for fall: Sep 11 to Sep 25
Sow outdoors: Mar 24 to Apr 14
Sow outdoors: Mar 31 to Apr 28Plant for fall: Sep 11 to Sep 25
Sow outdoors: Mar 31 to Apr 21Plant for fall: Sep 25 to Oct 16
Sow outdoors: Apr 21 to May 12Plant for fall: Sep 4 to Sep 18
Sow outdoors: Apr 21 to May 5
Transplant outside: Apr 28 to May 19
Plant for fall: Nov 6 to Dec 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Grass Valley, CA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 20 – Feb 3 | Mar 17 – Mar 31 | — | — |
| Peppers | Feb 3 – Feb 17 | Apr 28 – May 12 | — | — |
| Eggplant | Feb 3 – Feb 17 | Apr 28 – May 12 | — | — |
| Tomatoes | Feb 17 – Mar 3 | Apr 21 – May 5 | — | — |
| Lettuce | Feb 17 – Mar 3 | Mar 24 – Apr 7 | Mar 17 – Apr 21 | Sep 25 – Oct 23 |
| Kale | Feb 17 – Mar 3 | Mar 17 – Mar 31 | Mar 17 – Mar 31 | Sep 11 – Oct 2 |
| Broccoli | Feb 17 – Mar 3 | Mar 31 – Apr 14 | — | Aug 14 – Sep 4 |
| Cabbage | Feb 17 – Mar 3 | Mar 24 – Apr 7 | — | Aug 14 – Sep 4 |
| Cauliflower | Feb 17 – Mar 3 | Mar 31 – Apr 14 | — | Aug 14 – Sep 4 |
| Okra | Mar 3 – Mar 17 | May 5 – May 19 | May 5 – May 19 | — |
| Basil | Mar 3 – Mar 17 | Apr 21 – May 5 | — | — |
| Peas | — | — | Mar 3 – Mar 24 | Aug 28 – Sep 18 |
| Spinach | — | — | Mar 3 – Mar 24 | Sep 25 – Oct 16 |
| Radishes | — | — | Mar 10 – Apr 21 | Oct 9 – Oct 30 |
| Cucumbers | Mar 17 – Mar 24 | Apr 28 – May 5 | Apr 21 – May 5 | Sep 4 – Sep 18 |
| Zucchini & Summer Squash | Mar 17 – Mar 24 | — | Apr 21 – May 5 | Sep 11 – Sep 25 |
| Winter Squash & Pumpkins | Mar 17 – Mar 24 | — | Apr 21 – May 5 | — |
| Melons & Watermelon | Mar 17 – Mar 24 | Apr 28 – May 12 | — | — |
| Carrots | — | — | Mar 24 – Apr 21 | Aug 28 – Sep 11 |
| Beets | — | — | Mar 24 – Apr 21 | Sep 11 – Sep 25 |
| Potatoes | — | — | Mar 24 – Apr 14 | — |
| Swiss Chard | — | — | Mar 31 – Apr 28 | Sep 11 – Sep 25 |
| Cilantro | — | — | Mar 31 – Apr 21 | Sep 25 – Oct 16 |
| Green Beans | — | — | Apr 21 – May 12 | Sep 4 – Sep 18 |
| Sweet Corn | — | — | Apr 21 – May 5 | — |
| Sweet Potatoes | — | Apr 28 – May 19 | — | — |
| Garlic | — | — | — | Nov 6 – Dec 11 |
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 Nevada City, CA weather station, 4 km away (elevation 2,782 ft (848 m)).
ZIP codes in Grass Valley: 95945 95949
Frost dates near Grass Valley
- Cedar Ridge Apr 10 · Nov 13
- Chicago Park Apr 3 · Nov 24
- Nevada City Apr 14 · Nov 20
- Rough And Ready Apr 10 · Nov 13
- Gold Run Apr 3 · Nov 24
- Colfax Apr 3 · Nov 24
- Dutch Flat May 4 · Nov 4
- Penn Valley Apr 10 · Nov 13
Frequently asked questions
When is the last frost in Grass Valley, CA?
The median last spring frost in Grass Valley, CA is April 14. There is still about a 10% chance of frost after May 7, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Grass Valley, CA?
The median first fall frost is November 20, with about a 10% chance of frost before October 23.
How long is the growing season in Grass Valley, CA?
About 220 days between the median last spring frost and first fall frost.
What planting zone is Grass Valley, CA?
Grass Valley, CA is in USDA hardiness zone 9a.