Frost dates for 81525Mack, CO
The average last spring frost in Mack is April 27 and the average first fall frost is October 11, giving a typical growing season of about 164 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 27
- Average first fall frost
- Oct 11
- Growing season
- 164 days
Safer after May 7 (1-in-10 risk)
Possible by Sep 28 (1-in-10 risk)
Last frost typically in 182 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 28 · May 8 · May 21 | Sep 21 · Oct 1 · Oct 14 | 144 days | 100% |
| Frost / freeze (32°F) | Apr 17 · Apr 27 · May 7 | Sep 28 · Oct 11 · Oct 25 | 164 days | 100% |
| Hard freeze (28°F) | Apr 5 · Apr 18 · Apr 29 | Oct 6 · Oct 22 · Nov 5 | 185 days | 100% |
Planting calendar for Mack
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 27 – Jun 2 |
| Tomatoes | Transplant outdoors | May 13 – Jun 21 |
| Peppers | Start seeds indoors | Mar 27 – Apr 27 |
| Peppers | Transplant outdoors | May 27 – Jun 27 |
| Eggplant | Start seeds indoors | Apr 13 – May 12 |
| Eggplant | Transplant outdoors | May 27 – Jun 27 |
| Cucumbers | Sow outdoors | May 27 – Jul 1 |
| Summer squash | Sow outdoors | May 13 – Jun 27 |
| Winter squash & pumpkins | Sow outdoors | May 27 – Jun 27 |
| Snap beans | Sow outdoors | May 13 – Jul 24 |
| Sweet corn | Sow outdoors | May 13 – Jun 21 |
| Watermelon & cantaloupe | Sow outdoors | May 27 – Jun 27 |
| Okra | Sow outdoors | May 20 – Jun 12 |
| Peas | Sow outdoors (spring) | Mar 27 – May 12 |
| Potatoes | Plant outdoors (spring) | Mar 27 – May 27 |
| Onions | Start seeds indoors (spring) | Feb 13 – Mar 12 |
| Onions | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (spring) | Mar 9 – Apr 12 |
| Broccoli | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (fall) | Jun 11 – Jun 21 |
| Broccoli | Transplant outdoors (fall) | Jul 11 – Jul 22 |
| Cabbage | Start seeds indoors (spring) | Feb 27 – Mar 27 |
| Cabbage | Transplant outdoors (spring) | Mar 27 – Apr 27 |
| Cabbage | Start seeds indoors (fall) | Jun 1 – Jul 1 |
| Cabbage | Transplant outdoors (fall) | Jul 1 – Aug 1 |
| Leaf lettuce | Sow outdoors (spring) | Mar 27 – Jun 12 |
| Leaf lettuce | Sow outdoors (fall) | Jul 1 – Aug 17 |
| Spinach | Sow outdoors (spring) | Mar 20 – May 3 |
| Spinach | Sow outdoors (fall) | Jul 18 – Aug 22 |
| Radishes | Sow outdoors (spring) | Mar 27 – May 17 |
| Radishes | Sow outdoors (fall) | Jul 1 – Sep 1 |
| Kale | Sow outdoors (spring) | Apr 13 – May 3 |
| Kale | Sow outdoors (fall) | Jun 24 – Aug 1 |
| Carrots | Sow outdoors (spring) | Apr 27 – Jun 12 |
| Carrots | Sow outdoors (fall) | Jun 1 – Jul 17 |
| Garlic | Plant outdoors (fall) | Oct 1 – Nov 1 |
Where these dates come from
ZIP code 81525 is matched to the NOAA station Fruita, CO, 21.3 km away, at 4,498 ft elevation (102 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Fruita, CO (used) | 4,498 ft | Apr 27 | Oct 11 |
| Colorado Nm, CO | 5,781 ft | Apr 26 | Oct 16 |
| Glade Park 17W, CO | 6,323 ft | May 21 | Sep 26 |
| Grand Junction Walker Fld, CO | 4,858 ft | Apr 28 | Oct 16 |
Frost dates near Mack
- Loma, CO 81524 · last Apr 27, first Oct 11
- Fruita, CO 81521 · last Apr 27, first Oct 11
- Glade Park, CO 81523 · last May 21, first Sep 26
- Grand Junction, CO 81505 · last Apr 28, first Oct 16
- Clifton, CO 81520 · last Apr 23, first Oct 20
- Cisco, UT 84515 · last Apr 27, first Oct 9
- Palisade, CO 81526 · last Apr 17, first Oct 26
- Whitewater, CO 81527 · last Apr 23, first Oct 20
Frequently asked questions
- When is the last frost in Mack, CO?
- For ZIP code 81525, the average last spring frost (32°F) is April 27, based on NOAA 1991-2020 climate normals for the Fruita, CO weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Mack, CO?
- The average first fall frost (32°F) is October 11. There is a 1-in-10 chance of frost by September 28, so tender plants are at risk from that point on.
- How long is the growing season in 81525?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 164 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.