Frost dates for 81091Weston, CO
The average last spring frost in Weston is May 21 and the average first fall frost is September 29, giving a typical growing season of about 128 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 21
- Average first fall frost
- Sep 29
- Growing season
- 128 days
Safer after Jun 4 (1-in-10 risk)
Possible by Sep 16 (1-in-10 risk)
Last frost typically in 201 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) | May 21 · Jun 3 · Jun 17 | Sep 6 · Sep 20 · Sep 30 | 106 days | 100% |
| Frost / freeze (32°F) | May 8 · May 21 · Jun 4 | Sep 16 · Sep 29 · Oct 10 | 128 days | 100% |
| Hard freeze (28°F) | Apr 28 · May 10 · May 23 | Sep 24 · Oct 7 · Oct 19 | 148 days | 100% |
Planting calendar for Weston
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 20 – Jun 26 |
| Tomatoes | Transplant outdoors | Jun 6 – Jun 9 |
| Peppers | Start seeds indoors | Apr 20 – May 21 |
| Peppers | Transplant outdoors | Jun 20 – Jul 21 |
| Eggplant | Start seeds indoors | May 7 – Jun 5 |
| Eggplant | Transplant outdoors | Jun 20 – Jul 21 |
| Cucumbers | Sow outdoors | Jun 20 – Jun 19 |
| Summer squash | Sow outdoors | Jun 6 – Jul 21 |
| Winter squash & pumpkins | Sow outdoors | Jun 20 – Jul 21 |
| Snap beans | Sow outdoors | Jun 6 – Jul 12 |
| Sweet corn | Sow outdoors | Jun 6 – Jun 9 |
| Watermelon & cantaloupe | Sow outdoors | Jun 20 – Jul 21 |
| Okra | Sow outdoors | Jun 13 – Jul 6 |
| Peas | Sow outdoors (spring) | Apr 20 – Jun 5 |
| Potatoes | Plant outdoors (spring) | Apr 20 – Jun 20 |
| Onions | Start seeds indoors (spring) | Mar 9 – Apr 5 |
| Onions | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (spring) | Apr 2 – May 6 |
| Broccoli | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (fall) | May 30 – Jun 9 |
| Broccoli | Transplant outdoors (fall) | Jun 29 – Jul 10 |
| Cabbage | Start seeds indoors (spring) | Mar 23 – Apr 20 |
| Cabbage | Transplant outdoors (spring) | Apr 20 – May 21 |
| Cabbage | Start seeds indoors (fall) | May 20 – Jun 19 |
| Cabbage | Transplant outdoors (fall) | Jun 19 – Jul 20 |
| Leaf lettuce | Sow outdoors (spring) | Apr 20 – Jul 6 |
| Leaf lettuce | Sow outdoors (fall) | Jun 19 – Aug 5 |
| Spinach | Sow outdoors (spring) | Apr 13 – May 27 |
| Spinach | Sow outdoors (fall) | Jul 6 – Aug 10 |
| Radishes | Sow outdoors (spring) | Apr 20 – Jun 10 |
| Radishes | Sow outdoors (fall) | Jun 19 – Aug 20 |
| Kale | Sow outdoors (spring) | May 7 – May 27 |
| Kale | Sow outdoors (fall) | Jun 12 – Jul 20 |
| Carrots | Sow outdoors (spring) | May 21 – Jul 6 |
| Carrots | Sow outdoors (fall) | May 20 – Jul 5 |
| Garlic | Plant outdoors (fall) | Sep 19 – Oct 20 |
Where these dates come from
ZIP code 81091 is matched to the NOAA station Lake Maloya, NM, 45 km away, at 7,400 ft elevation (100 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Lake Maloya, NM (used) | 7,400 ft | May 21 | Sep 29 |
| Trinidad Lake, CO | 6,310 ft | May 11 | Oct 4 |
| Trinidad, CO | 6,030 ft | Apr 30 | Oct 15 |
| Trinidad Perry Stokes Ap, CO | 5,741 ft | May 4 | Oct 9 |
Frost dates near Weston
- Boncarbo, CO 81024 · last May 5, first Oct 9
- Aguilar, CO 81020 · last May 11, first Oct 4
- Trinidad, CO 81082 · last Apr 30, first Oct 15
- Hoehne, CO 81046 · last May 4, first Oct 9
- La Veta, CO 81055 · last May 27, first Sep 25
- Raton, NM 87740 · last May 19, first Sep 29
- Chama, CO 81126 · last May 31, first Sep 23
- Walsenburg, CO 81089 · last May 6, first Oct 4
Frequently asked questions
- When is the last frost in Weston, CO?
- For ZIP code 81091, the average last spring frost (32°F) is May 21, based on NOAA 1991-2020 climate normals for the Lake Maloya, NM weather station. There is a 1-in-10 chance of a frost after June 4.
- When is the first frost in Weston, CO?
- The average first fall frost (32°F) is September 29. There is a 1-in-10 chance of frost by September 16, so tender plants are at risk from that point on.
- How long is the growing season in 81091?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 128 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.