Frost dates for 95949Grass Valley, CA
The average last spring frost in Grass Valley is April 10 and the average first fall frost is November 13, giving a typical growing season of about 215 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 10
- Average first fall frost
- Nov 13
- Growing season
- 215 days
Safer after Apr 30 (1-in-10 risk)
Possible by Oct 26 (1-in-10 risk)
First frost typically in 10 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) | Apr 13 · Apr 28 · May 20 | Oct 11 · Oct 31 · Nov 13 | 182 days | 100% |
| Frost / freeze (32°F) | Mar 17 · Apr 10 · Apr 30 | Oct 26 · Nov 13 · Dec 1 | 215 days | 100% |
| Hard freeze (28°F) | Jan 31 · Mar 9 · Apr 8 | Nov 11 · Dec 1 · Dec 21 | 268 days | 100% |
Planting calendar for Grass Valley
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 | Mar 10 – May 16 |
| Tomatoes | Transplant outdoors | Apr 26 – Jul 24 |
| Peppers | Start seeds indoors | Mar 10 – Apr 10 |
| Peppers | Transplant outdoors | May 10 – Jun 10 |
| Eggplant | Start seeds indoors | Mar 27 – Apr 25 |
| Eggplant | Transplant outdoors | May 10 – Jun 10 |
| Cucumbers | Sow outdoors | May 10 – Aug 3 |
| Summer squash | Sow outdoors | Apr 26 – Jun 10 |
| Winter squash & pumpkins | Sow outdoors | May 10 – Jun 10 |
| Snap beans | Sow outdoors | Apr 26 – Aug 26 |
| Sweet corn | Sow outdoors | Apr 26 – Jul 24 |
| Watermelon & cantaloupe | Sow outdoors | May 10 – Jun 10 |
| Okra | Sow outdoors | May 3 – May 26 |
| Peas | Sow outdoors (spring) | Mar 10 – Apr 25 |
| Potatoes | Plant outdoors (spring) | Mar 10 – May 10 |
| Onions | Start seeds indoors (spring) | Jan 27 – Feb 23 |
| Onions | Transplant outdoors (spring) | Mar 27 – Apr 25 |
| Broccoli | Start seeds indoors (spring) | Feb 20 – Mar 26 |
| Broccoli | Transplant outdoors (spring) | Mar 27 – Apr 25 |
| Broccoli | Start seeds indoors (fall) | Jul 14 – Jul 24 |
| Broccoli | Transplant outdoors (fall) | Aug 13 – Aug 24 |
| Cabbage | Start seeds indoors (spring) | Feb 10 – Mar 10 |
| Cabbage | Transplant outdoors (spring) | Mar 10 – Apr 10 |
| Cabbage | Start seeds indoors (fall) | Jul 4 – Aug 3 |
| Cabbage | Transplant outdoors (fall) | Aug 3 – Sep 3 |
| Leaf lettuce | Sow outdoors (spring) | Mar 10 – May 26 |
| Leaf lettuce | Sow outdoors (fall) | Aug 3 – Sep 19 |
| Spinach | Sow outdoors (spring) | Mar 3 – Apr 16 |
| Spinach | Sow outdoors (fall) | Aug 20 – Sep 24 |
| Radishes | Sow outdoors (spring) | Mar 10 – Apr 30 |
| Radishes | Sow outdoors (fall) | Aug 3 – Oct 4 |
| Kale | Sow outdoors (spring) | Mar 27 – Apr 16 |
| Kale | Sow outdoors (fall) | Jul 27 – Sep 3 |
| Carrots | Sow outdoors (spring) | Apr 10 – May 26 |
| Carrots | Sow outdoors (fall) | Jul 4 – Aug 19 |
| Garlic | Plant outdoors (fall) | Nov 3 – Dec 4 |
Where these dates come from
ZIP code 95949 is matched to the NOAA station Grass Valley #2, CA, 9.7 km away, at 2,400 ft elevation (281 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Grass Valley #2, CA (used) | 2,400 ft | Apr 10 | Nov 13 |
| Colfax, CA | 2,380 ft | Apr 3 | Nov 24 |
| Nevada City, CA | 2,781 ft | Apr 14 | Nov 20 |
| Auburn, CA | 1,292 ft | Feb 25 | Dec 5 |
Frost dates near Grass Valley
- Cedar Ridge, CA 95924 · last Apr 14, first Nov 20
- Chicago Park, CA 95712 · last Apr 3, first Nov 24
- Grass Valley, CA 95945 · last Apr 14, first Nov 20
- Colfax, CA 95713 · last Apr 3, first Nov 24
- Rough And Ready, CA 95975 · last Apr 1, first Nov 17
- Penn Valley, CA 95946 · last Apr 1, first Nov 17
- Weimar, CA 95736 · last Apr 3, first Nov 24
- Meadow Vista, CA 95722 · last Feb 25, first Dec 5
Frequently asked questions
- When is the last frost in Grass Valley, CA?
- For ZIP code 95949, the average last spring frost (32°F) is April 10, based on NOAA 1991-2020 climate normals for the Grass Valley #2, CA weather station. There is a 1-in-10 chance of a frost after April 30.
- When is the first frost in Grass Valley, CA?
- The average first fall frost (32°F) is November 13. There is a 1-in-10 chance of frost by October 26, so tender plants are at risk from that point on.
- How long is the growing season in 95949?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 215 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.