Frost dates for 91948Mount Laguna, CA
The average last spring frost in Mount Laguna is April 22 and the average first fall frost is November 8, giving a typical growing season of about 197 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 22
- Average first fall frost
- Nov 8
- Growing season
- 197 days
Safer after May 21 (1-in-10 risk)
Possible by Oct 10 (1-in-10 risk)
First frost typically in 7 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 15 · May 10 · Jun 2 | Oct 1 · Oct 23 · Nov 13 | 164 days | 100% |
| Frost / freeze (32°F) | Mar 25 · Apr 22 · May 21 | Oct 10 · Nov 8 · Dec 4 | 197 days | 100% |
| Hard freeze (28°F) | Feb 22 · Apr 2 · May 8 | Nov 2 · Dec 1 · Dec 25 | 236 days | 100% |
Planting calendar for Mount Laguna
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 22 – May 28 |
| Tomatoes | Transplant outdoors | May 8 – Jul 19 |
| Peppers | Start seeds indoors | Mar 22 – Apr 22 |
| Peppers | Transplant outdoors | May 22 – Jun 22 |
| Eggplant | Start seeds indoors | Apr 8 – May 7 |
| Eggplant | Transplant outdoors | May 22 – Jun 22 |
| Cucumbers | Sow outdoors | May 22 – Jul 29 |
| Summer squash | Sow outdoors | May 8 – Jun 22 |
| Winter squash & pumpkins | Sow outdoors | May 22 – Jun 22 |
| Snap beans | Sow outdoors | May 8 – Aug 21 |
| Sweet corn | Sow outdoors | May 8 – Jul 19 |
| Watermelon & cantaloupe | Sow outdoors | May 22 – Jun 22 |
| Okra | Sow outdoors | May 15 – Jun 7 |
| Peas | Sow outdoors (spring) | Mar 22 – May 7 |
| Potatoes | Plant outdoors (spring) | Mar 22 – May 22 |
| Onions | Start seeds indoors (spring) | Feb 8 – Mar 7 |
| Onions | Transplant outdoors (spring) | Apr 8 – May 7 |
| Broccoli | Start seeds indoors (spring) | Mar 4 – Apr 7 |
| Broccoli | Transplant outdoors (spring) | Apr 8 – May 7 |
| Broccoli | Start seeds indoors (fall) | Jul 9 – Jul 19 |
| Broccoli | Transplant outdoors (fall) | Aug 8 – Aug 19 |
| Cabbage | Start seeds indoors (spring) | Feb 22 – Mar 22 |
| Cabbage | Transplant outdoors (spring) | Mar 22 – Apr 22 |
| Cabbage | Start seeds indoors (fall) | Jun 29 – Jul 29 |
| Cabbage | Transplant outdoors (fall) | Jul 29 – Aug 29 |
| Leaf lettuce | Sow outdoors (spring) | Mar 22 – Jun 7 |
| Leaf lettuce | Sow outdoors (fall) | Jul 29 – Sep 14 |
| Spinach | Sow outdoors (spring) | Mar 15 – Apr 28 |
| Spinach | Sow outdoors (fall) | Aug 15 – Sep 19 |
| Radishes | Sow outdoors (spring) | Mar 22 – May 12 |
| Radishes | Sow outdoors (fall) | Jul 29 – Sep 29 |
| Kale | Sow outdoors (spring) | Apr 8 – Apr 28 |
| Kale | Sow outdoors (fall) | Jul 22 – Aug 29 |
| Carrots | Sow outdoors (spring) | Apr 22 – Jun 7 |
| Carrots | Sow outdoors (fall) | Jun 29 – Aug 14 |
| Garlic | Plant outdoors (fall) | Oct 29 – Nov 29 |
Where these dates come from
ZIP code 91948 is matched to the NOAA station Mt Laguna #3, CA, 0.1 km away, at 5,920 ft elevation (37 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mt Laguna #3, CA (used) | 5,920 ft | Apr 22 | Nov 8 |
| Cuyamaca, CA | 4,640 ft | Apr 19 | Oct 27 |
| Campo, CA | 2,630 ft | Apr 30 | Oct 26 |
| Campo Asos, CA | 2,641 ft | Apr 29 | Nov 1 |
Frost dates near Mount Laguna
- Pine Valley, CA 91962 · last Mar 27, first Dec 1
- Guatay, CA 91931 · last Mar 27, first Dec 1
- Descanso, CA 91916 · last Mar 27, first Dec 1
- Boulevard, CA 91905 · last Mar 27, first Dec 1
- Campo, CA 91906 · last Apr 29, first Nov 1
- Julian, CA 92036 · last Mar 27, first Dec 1
- Alpine, CA 91901 · last Feb 12, first Dec 24
- Potrero, CA 91963 · last Apr 30, first Oct 26
Frequently asked questions
- When is the last frost in Mount Laguna, CA?
- For ZIP code 91948, the average last spring frost (32°F) is April 22, based on NOAA 1991-2020 climate normals for the Mt Laguna #3, CA weather station. There is a 1-in-10 chance of a frost after May 21.
- When is the first frost in Mount Laguna, CA?
- The average first fall frost (32°F) is November 8. There is a 1-in-10 chance of frost by October 10, so tender plants are at risk from that point on.
- How long is the growing season in 91948?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 197 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.