Frost dates for 92366Mountain Pass, CA
The average last spring frost in Mountain Pass is March 6 and the average first fall frost is December 8, giving a typical growing season of about 272 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 6
- Average first fall frost
- Dec 8
- Growing season
- 272 days
Safer after Apr 9 (1-in-10 risk)
Possible by Nov 12 (1-in-10 risk)
First frost typically in 35 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) | Feb 27 · Apr 1 · May 2 | Oct 30 · Nov 24 · Dec 14 | 231 days | 100% |
| Frost / freeze (32°F) | Jan 17 · Mar 6 · Apr 9 | Nov 12 · Dec 8 · Jan 5 | 272 days | 99% |
| Hard freeze (28°F) | Dec 21 · Feb 1 · Mar 20 | Nov 25 · Dec 25 · Feb 13 | 329 days | 80% |
Planting calendar for Mountain Pass
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 | Feb 3 – Apr 11 |
| Tomatoes | Transplant outdoors | Mar 22 – Aug 18 |
| Peppers | Start seeds indoors | Feb 3 – Mar 6 |
| Peppers | Transplant outdoors | Apr 5 – May 6 |
| Eggplant | Start seeds indoors | Feb 20 – Mar 21 |
| Eggplant | Transplant outdoors | Apr 5 – May 6 |
| Cucumbers | Sow outdoors | Apr 5 – Aug 28 |
| Summer squash | Sow outdoors | Mar 22 – May 6 |
| Winter squash & pumpkins | Sow outdoors | Apr 5 – May 6 |
| Snap beans | Sow outdoors | Mar 22 – Sep 20 |
| Sweet corn | Sow outdoors | Mar 22 – Aug 18 |
| Watermelon & cantaloupe | Sow outdoors | Apr 5 – May 6 |
| Okra | Sow outdoors | Mar 29 – Apr 21 |
| Peas | Sow outdoors (spring) | Feb 3 – Mar 21 |
| Potatoes | Plant outdoors (spring) | Feb 3 – Apr 5 |
| Onions | Start seeds indoors (spring) | Dec 23 – Jan 19 |
| Onions | Transplant outdoors (spring) | Feb 20 – Mar 21 |
| Broccoli | Start seeds indoors (spring) | Jan 16 – Feb 19 |
| Broccoli | Transplant outdoors (spring) | Feb 20 – Mar 21 |
| Broccoli | Start seeds indoors (fall) | Aug 8 – Aug 18 |
| Broccoli | Transplant outdoors (fall) | Sep 7 – Sep 18 |
| Cabbage | Start seeds indoors (spring) | Jan 6 – Feb 3 |
| Cabbage | Transplant outdoors (spring) | Feb 3 – Mar 6 |
| Cabbage | Start seeds indoors (fall) | Jul 29 – Aug 28 |
| Cabbage | Transplant outdoors (fall) | Aug 28 – Sep 28 |
| Leaf lettuce | Sow outdoors (spring) | Feb 3 – Apr 21 |
| Leaf lettuce | Sow outdoors (fall) | Aug 28 – Oct 14 |
| Spinach | Sow outdoors (spring) | Jan 27 – Mar 12 |
| Spinach | Sow outdoors (fall) | Sep 14 – Oct 19 |
| Radishes | Sow outdoors (spring) | Feb 3 – Mar 26 |
| Radishes | Sow outdoors (fall) | Aug 28 – Oct 29 |
| Kale | Sow outdoors (spring) | Feb 20 – Mar 12 |
| Kale | Sow outdoors (fall) | Aug 21 – Sep 28 |
| Carrots | Sow outdoors (spring) | Mar 6 – Apr 21 |
| Carrots | Sow outdoors (fall) | Jul 29 – Sep 13 |
| Garlic | Plant outdoors (fall) | Nov 28 – Dec 29 |
Where these dates come from
ZIP code 92366 is matched to the NOAA station Mitchell Caverns, CA, 58.6 km away, at 4,350 ft elevation (371 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mitchell Caverns, CA (used) | 4,350 ft | Mar 6 | Dec 8 |
| Goodsprings, NV | 3,716 ft | Mar 17 | Nov 20 |
| Baker, CA | 962 ft | Feb 14 | Nov 27 |
| Searchlight, NV | 3,540 ft | Mar 7 | Nov 29 |
Frost dates near Mountain Pass
- Nipton, CA 92364 · last Mar 7, first Nov 29
- Cima, CA 92323 · last Mar 6, first Dec 8
- Jean, NV 89019 · last Feb 4, first Dec 5
- Baker, CA 92309 · last Feb 14, first Nov 27
- Henderson, NV 89044 · last Feb 4, first Dec 5
- Searchlight, NV 89046 · last Mar 7, first Nov 29
- Sloan, NV 89054 · last Feb 4, first Dec 5
- Las Vegas, NV 89161 · last Mar 13, first Nov 15
Frequently asked questions
- When is the last frost in Mountain Pass, CA?
- For ZIP code 92366, the average last spring frost (32°F) is March 6, based on NOAA 1991-2020 climate normals for the Mitchell Caverns, CA weather station. There is a 1-in-10 chance of a frost after April 9.
- When is the first frost in Mountain Pass, CA?
- The average first fall frost (32°F) is December 8. There is a 1-in-10 chance of frost by November 12, so tender plants are at risk from that point on.
- How long is the growing season in 92366?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 272 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.