Frost dates for 87545Los Alamos, NM
The average last spring frost in Los Alamos is May 2 and the average first fall frost is October 12, giving a typical growing season of about 162 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 2
- Average first fall frost
- Oct 12
- Growing season
- 162 days
Safer after May 17 (1-in-10 risk)
Possible by Oct 1 (1-in-10 risk)
Last frost typically in 180 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 30 · May 16 · May 31 | Sep 19 · Oct 4 · Oct 17 | 140 days | 100% |
| Frost / freeze (32°F) | Apr 19 · May 2 · May 17 | Oct 1 · Oct 12 · Oct 25 | 162 days | 100% |
| Hard freeze (28°F) | Apr 6 · Apr 20 · May 4 | Oct 9 · Oct 23 · Nov 6 | 182 days | 100% |
Planting calendar for Los Alamos
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 1 – Jun 7 |
| Tomatoes | Transplant outdoors | May 18 – Jun 22 |
| Peppers | Start seeds indoors | Apr 1 – May 2 |
| Peppers | Transplant outdoors | Jun 1 – Jul 2 |
| Eggplant | Start seeds indoors | Apr 18 – May 17 |
| Eggplant | Transplant outdoors | Jun 1 – Jul 2 |
| Cucumbers | Sow outdoors | Jun 1 – Jul 2 |
| Summer squash | Sow outdoors | May 18 – Jul 2 |
| Winter squash & pumpkins | Sow outdoors | Jun 1 – Jul 2 |
| Snap beans | Sow outdoors | May 18 – Jul 25 |
| Sweet corn | Sow outdoors | May 18 – Jun 22 |
| Watermelon & cantaloupe | Sow outdoors | Jun 1 – Jul 2 |
| Okra | Sow outdoors | May 25 – Jun 17 |
| Peas | Sow outdoors (spring) | Apr 1 – May 17 |
| Potatoes | Plant outdoors (spring) | Apr 1 – Jun 1 |
| Onions | Start seeds indoors (spring) | Feb 18 – Mar 17 |
| Onions | Transplant outdoors (spring) | Apr 18 – May 17 |
| Broccoli | Start seeds indoors (spring) | Mar 14 – Apr 17 |
| Broccoli | Transplant outdoors (spring) | Apr 18 – May 17 |
| Broccoli | Start seeds indoors (fall) | Jun 12 – Jun 22 |
| Broccoli | Transplant outdoors (fall) | Jul 12 – Jul 23 |
| Cabbage | Start seeds indoors (spring) | Mar 4 – Apr 1 |
| Cabbage | Transplant outdoors (spring) | Apr 1 – May 2 |
| Cabbage | Start seeds indoors (fall) | Jun 2 – Jul 2 |
| Cabbage | Transplant outdoors (fall) | Jul 2 – Aug 2 |
| Leaf lettuce | Sow outdoors (spring) | Apr 1 – Jun 17 |
| Leaf lettuce | Sow outdoors (fall) | Jul 2 – Aug 18 |
| Spinach | Sow outdoors (spring) | Mar 25 – May 8 |
| Spinach | Sow outdoors (fall) | Jul 19 – Aug 23 |
| Radishes | Sow outdoors (spring) | Apr 1 – May 22 |
| Radishes | Sow outdoors (fall) | Jul 2 – Sep 2 |
| Kale | Sow outdoors (spring) | Apr 18 – May 8 |
| Kale | Sow outdoors (fall) | Jun 25 – Aug 2 |
| Carrots | Sow outdoors (spring) | May 2 – Jun 17 |
| Carrots | Sow outdoors (fall) | Jun 2 – Jul 18 |
| Garlic | Plant outdoors (fall) | Oct 2 – Nov 2 |
Where these dates come from
ZIP code 87545 is matched to the NOAA station Los Alamos, NM, 2.4 km away, at 7,424 ft elevation (222 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Los Alamos, NM (used) | 7,424 ft | May 2 | Oct 12 |
| Los Alamos 13 W, NM | 8,716 ft | Jun 10 | Sep 13 |
| Cochiti Dam, NM | 5,560 ft | Apr 26 | Oct 21 |
| Espanola, NM | 5,620 ft | May 11 | Oct 6 |
Frost dates near Los Alamos
- Los Alamos, NM 87544 · last May 2, first Oct 12
- White Rock, NM 87547 · last May 4, first Oct 15
- Cochiti Lake, NM 87083 · last Apr 26, first Oct 21
- Espanola, NM 87532 · last May 11, first Oct 6
- Hernandez, NM 87537 · last May 10, first Oct 4
- Santa Cruz, NM 87567 · last May 11, first Oct 6
- Santa Fe, NM 87506 · last May 4, first Oct 15
- Cochiti Pueblo, NM 87072 · last Apr 26, first Oct 21
Frequently asked questions
- When is the last frost in Los Alamos, NM?
- For ZIP code 87545, the average last spring frost (32°F) is May 2, based on NOAA 1991-2020 climate normals for the Los Alamos, NM weather station. There is a 1-in-10 chance of a frost after May 17.
- When is the first frost in Los Alamos, NM?
- The average first fall frost (32°F) is October 12. There is a 1-in-10 chance of frost by October 1, so tender plants are at risk from that point on.
- How long is the growing season in 87545?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 162 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.