Frost dates for 81403Montrose, CO
The average last spring frost in Montrose is June 11 and the average first fall frost is September 13, giving a typical growing season of about 92 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 11
- Average first fall frost
- Sep 13
- Growing season
- 92 days
Safer after Jun 30 (1-in-10 risk)
Possible by Sep 1 (1-in-10 risk)
Last frost typically in 227 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) | — | — | 64 days | 100% |
| Frost / freeze (32°F) | May 27 · Jun 11 · Jun 30 | Sep 1 · Sep 13 · Sep 25 | 92 days | 100% |
| Hard freeze (28°F) | May 5 · May 26 · Jun 14 | Sep 10 · Sep 23 · Oct 4 | 117 days | 100% |
Planting calendar for Montrose
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 | May 11 – Jul 17 |
| Tomatoes | Transplant outdoors | Jun 27 – May 24 |
| Peppers | Start seeds indoors | May 11 – Jun 11 |
| Peppers | Transplant outdoors | Jul 11 – Aug 11 |
| Eggplant | Start seeds indoors | May 28 – Jun 26 |
| Eggplant | Transplant outdoors | Jul 11 – Aug 11 |
| Cucumbers | Sow outdoors | Jul 11 – Jun 3 |
| Summer squash | Sow outdoors | Jun 27 – Aug 11 |
| Winter squash & pumpkins | Sow outdoors | Jul 11 – Aug 11 |
| Snap beans | Sow outdoors | Jun 27 – Jun 26 |
| Sweet corn | Sow outdoors | Jun 27 – May 24 |
| Watermelon & cantaloupe | Sow outdoors | Jul 11 – Aug 11 |
| Okra | Sow outdoors | Jul 4 – Jul 27 |
| Peas | Sow outdoors (spring) | May 11 – Jun 26 |
| Potatoes | Plant outdoors (spring) | May 11 – Jul 11 |
| Onions | Start seeds indoors (spring) | Mar 30 – Apr 26 |
| Onions | Transplant outdoors (spring) | May 28 – Jun 26 |
| Broccoli | Start seeds indoors (spring) | Apr 23 – May 27 |
| Broccoli | Transplant outdoors (spring) | May 28 – Jun 26 |
| Broccoli | Start seeds indoors (fall) | May 14 – May 24 |
| Broccoli | Transplant outdoors (fall) | Jun 13 – Jun 24 |
| Cabbage | Start seeds indoors (spring) | Apr 13 – May 11 |
| Cabbage | Transplant outdoors (spring) | May 11 – Jun 11 |
| Cabbage | Start seeds indoors (fall) | May 4 – Jun 3 |
| Cabbage | Transplant outdoors (fall) | Jun 3 – Jul 4 |
| Leaf lettuce | Sow outdoors (spring) | May 11 – Jul 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 3 – Jul 20 |
| Spinach | Sow outdoors (spring) | May 4 – Jun 17 |
| Spinach | Sow outdoors (fall) | Jun 20 – Jul 25 |
| Radishes | Sow outdoors (spring) | May 11 – Jul 1 |
| Radishes | Sow outdoors (fall) | Jun 3 – Aug 4 |
| Kale | Sow outdoors (spring) | May 28 – Jun 17 |
| Kale | Sow outdoors (fall) | May 27 – Jul 4 |
| Carrots | Sow outdoors (spring) | Jun 11 – Jul 27 |
| Carrots | Sow outdoors (fall) | May 4 – Jun 19 |
| Garlic | Plant outdoors (fall) | Sep 3 – Oct 4 |
Where these dates come from
ZIP code 81403 is matched to the NOAA station Ridgway, CO, 28.2 km away, at 7,049 ft elevation (41 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ridgway, CO (used) | 7,049 ft | Jun 11 | Sep 13 |
| Montrose #2, CO | 5,789 ft | Apr 28 | Oct 14 |
| Montrose Rgnl Ap, CO | 5,759 ft | May 2 | Oct 8 |
| Montrose 11 Ene, CO | 8,402 ft | May 20 | Oct 1 |
Frost dates near Montrose
- Montrose, CO 81401 · last Apr 28, first Oct 14
- Olathe, CO 81425 · last May 2, first Oct 8
- Ridgway, CO 81432 · last Jun 11, first Sep 13
- Placerville, CO 81430 · last May 26, first Sep 29
- Cimarron, CO 81220 · last Jun 9, first Sep 16
- Norwood, CO 81423 · last May 25, first Oct 1
- Delta, CO 81416 · last May 1, first Oct 7
- Ouray, CO 81427 · last May 17, first Oct 1
Frequently asked questions
- When is the last frost in Montrose, CO?
- For ZIP code 81403, the average last spring frost (32°F) is June 11, based on NOAA 1991-2020 climate normals for the Ridgway, CO weather station. There is a 1-in-10 chance of a frost after June 30.
- When is the first frost in Montrose, CO?
- The average first fall frost (32°F) is September 13. There is a 1-in-10 chance of frost by September 1, so tender plants are at risk from that point on.
- How long is the growing season in 81403?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 92 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.