Frost dates for 95701Alta, CA
The average last spring frost in Alta is May 4 and the average first fall frost is November 4, giving a typical growing season of about 183 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 4
- Average first fall frost
- Nov 4
- Growing season
- 183 days
Safer after May 31 (1-in-10 risk)
Possible by Oct 12 (1-in-10 risk)
First frost typically in 3 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 27 · May 22 · Jun 10 | Sep 28 · Oct 20 · Nov 10 | 153 days | 100% |
| Frost / freeze (32°F) | Apr 12 · May 4 · May 31 | Oct 12 · Nov 4 · Nov 26 | 183 days | 100% |
| Hard freeze (28°F) | Mar 17 · Apr 16 · May 13 | Nov 1 · Nov 23 · Dec 15 | 219 days | 100% |
Planting calendar for Alta
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 | Apr 3 – Jun 9 |
| Tomatoes | Transplant outdoors | May 20 – Jul 15 |
| Peppers | Start seeds indoors | Apr 3 – May 4 |
| Peppers | Transplant outdoors | Jun 3 – Jul 4 |
| Eggplant | Start seeds indoors | Apr 20 – May 19 |
| Eggplant | Transplant outdoors | Jun 3 – Jul 4 |
| Cucumbers | Sow outdoors | Jun 3 – Jul 25 |
| Summer squash | Sow outdoors | May 20 – Jul 4 |
| Winter squash & pumpkins | Sow outdoors | Jun 3 – Jul 4 |
| Snap beans | Sow outdoors | May 20 – Aug 17 |
| Sweet corn | Sow outdoors | May 20 – Jul 15 |
| Watermelon & cantaloupe | Sow outdoors | Jun 3 – Jul 4 |
| Okra | Sow outdoors | May 27 – Jun 19 |
| Peas | Sow outdoors (spring) | Apr 3 – May 19 |
| Potatoes | Plant outdoors (spring) | Apr 3 – Jun 3 |
| Onions | Start seeds indoors (spring) | Feb 20 – Mar 19 |
| Onions | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (spring) | Mar 16 – Apr 19 |
| Broccoli | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (fall) | Jul 5 – Jul 15 |
| Broccoli | Transplant outdoors (fall) | Aug 4 – Aug 15 |
| Cabbage | Start seeds indoors (spring) | Mar 6 – Apr 3 |
| Cabbage | Transplant outdoors (spring) | Apr 3 – May 4 |
| Cabbage | Start seeds indoors (fall) | Jun 25 – Jul 25 |
| Cabbage | Transplant outdoors (fall) | Jul 25 – Aug 25 |
| Leaf lettuce | Sow outdoors (spring) | Apr 3 – Jun 19 |
| Leaf lettuce | Sow outdoors (fall) | Jul 25 – Sep 10 |
| Spinach | Sow outdoors (spring) | Mar 27 – May 10 |
| Spinach | Sow outdoors (fall) | Aug 11 – Sep 15 |
| Radishes | Sow outdoors (spring) | Apr 3 – May 24 |
| Radishes | Sow outdoors (fall) | Jul 25 – Sep 25 |
| Kale | Sow outdoors (spring) | Apr 20 – May 10 |
| Kale | Sow outdoors (fall) | Jul 18 – Aug 25 |
| Carrots | Sow outdoors (spring) | May 4 – Jun 19 |
| Carrots | Sow outdoors (fall) | Jun 25 – Aug 10 |
| Garlic | Plant outdoors (fall) | Oct 25 – Nov 25 |
Where these dates come from
ZIP code 95701 is matched to the NOAA station Blue Canyon Ap, CA, 5.2 km away, at 5,276 ft elevation (794 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Blue Canyon Ap, CA (used) | 5,276 ft | May 4 | Nov 4 |
| Lake Spaulding, CA | 5,156 ft | May 22 | Oct 16 |
| Nevada City, CA | 2,781 ft | Apr 14 | Nov 20 |
| Colfax, CA | 2,380 ft | Apr 3 | Nov 24 |
Frost dates near Alta
- Dutch Flat, CA 95714 · last Apr 14, first Nov 20
- Emigrant Gap, CA 95715 · last May 4, first Nov 4
- Gold Run, CA 95717 · last Apr 14, first Nov 20
- Washington, CA 95986 · last Apr 14, first Nov 20
- Foresthill, CA 95631 · last Apr 12, first Nov 21
- Nevada City, CA 95959 · 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
Frequently asked questions
- When is the last frost in Alta, CA?
- For ZIP code 95701, the average last spring frost (32°F) is May 4, based on NOAA 1991-2020 climate normals for the Blue Canyon Ap, CA weather station. There is a 1-in-10 chance of a frost after May 31.
- When is the first frost in Alta, CA?
- The average first fall frost (32°F) is November 4. There is a 1-in-10 chance of frost by October 12, so tender plants are at risk from that point on.
- How long is the growing season in 95701?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 183 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.