Frost dates for 80751Sterling, CO
The average last spring frost in Sterling is April 30 and the average first fall frost is October 9, giving a typical growing season of about 161 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 30
- Average first fall frost
- Oct 9
- Growing season
- 161 days
Safer after May 12 (1-in-10 risk)
Possible by Sep 28 (1-in-10 risk)
Last frost typically in 185 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 11 · May 24 | Sep 18 · Oct 1 · Oct 11 | 142 days | 100% |
| Frost / freeze (32°F) | Apr 16 · Apr 30 · May 12 | Sep 28 · Oct 9 · Oct 20 | 161 days | 100% |
| Hard freeze (28°F) | Apr 4 · Apr 18 · May 3 | Oct 6 · Oct 18 · Oct 29 | 180 days | 100% |
Planting calendar for Sterling
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 30 – Jun 5 |
| Tomatoes | Transplant outdoors | May 16 – Jun 19 |
| Peppers | Start seeds indoors | Mar 30 – Apr 30 |
| Peppers | Transplant outdoors | May 30 – Jun 30 |
| Eggplant | Start seeds indoors | Apr 16 – May 15 |
| Eggplant | Transplant outdoors | May 30 – Jun 30 |
| Cucumbers | Sow outdoors | May 30 – Jun 29 |
| Summer squash | Sow outdoors | May 16 – Jun 30 |
| Winter squash & pumpkins | Sow outdoors | May 30 – Jun 30 |
| Snap beans | Sow outdoors | May 16 – Jul 22 |
| Sweet corn | Sow outdoors | May 16 – Jun 19 |
| Watermelon & cantaloupe | Sow outdoors | May 30 – Jun 30 |
| Okra | Sow outdoors | May 23 – Jun 15 |
| Peas | Sow outdoors (spring) | Mar 30 – May 15 |
| Potatoes | Plant outdoors (spring) | Mar 30 – May 30 |
| Onions | Start seeds indoors (spring) | Feb 16 – Mar 15 |
| Onions | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (spring) | Mar 12 – Apr 15 |
| Broccoli | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (fall) | Jun 9 – Jun 19 |
| Broccoli | Transplant outdoors (fall) | Jul 9 – Jul 20 |
| Cabbage | Start seeds indoors (spring) | Mar 2 – Mar 30 |
| Cabbage | Transplant outdoors (spring) | Mar 30 – Apr 30 |
| Cabbage | Start seeds indoors (fall) | May 30 – Jun 29 |
| Cabbage | Transplant outdoors (fall) | Jun 29 – Jul 30 |
| Leaf lettuce | Sow outdoors (spring) | Mar 30 – Jun 15 |
| Leaf lettuce | Sow outdoors (fall) | Jun 29 – Aug 15 |
| Spinach | Sow outdoors (spring) | Mar 23 – May 6 |
| Spinach | Sow outdoors (fall) | Jul 16 – Aug 20 |
| Radishes | Sow outdoors (spring) | Mar 30 – May 20 |
| Radishes | Sow outdoors (fall) | Jun 29 – Aug 30 |
| Kale | Sow outdoors (spring) | Apr 16 – May 6 |
| Kale | Sow outdoors (fall) | Jun 22 – Jul 30 |
| Carrots | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Carrots | Sow outdoors (fall) | May 30 – Jul 15 |
| Garlic | Plant outdoors (fall) | Sep 29 – Oct 30 |
Where these dates come from
ZIP code 80751 is matched to the NOAA station Sterling, CO, 1.1 km away, at 3,974 ft elevation (37 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Sterling, CO (used) | 3,974 ft | Apr 30 | Oct 9 |
| Leroy 5 Wsw, CO | 4,467 ft | May 10 | Oct 6 |
| Fleming 3Sw, CO | 4,256 ft | May 4 | Oct 11 |
| Crook, CO | 3,709 ft | May 11 | Oct 4 |
Frost dates near Sterling
- Atwood, CO 80722 · last Apr 30, first Oct 9
- Iliff, CO 80736 · last Apr 30, first Oct 9
- Merino, CO 80741 · last May 10, first Oct 6
- Fleming, CO 80728 · last May 4, first Oct 11
- Padroni, CO 80745 · last May 15, first Sep 30
- Stoneham, CO 80754 · last May 9, first Oct 4
- Peetz, CO 80747 · last May 15, first Sep 30
- Hillrose, CO 80733 · last May 6, first Oct 6
Frequently asked questions
- When is the last frost in Sterling, CO?
- For ZIP code 80751, the average last spring frost (32°F) is April 30, based on NOAA 1991-2020 climate normals for the Sterling, CO weather station. There is a 1-in-10 chance of a frost after May 12.
- When is the first frost in Sterling, CO?
- The average first fall frost (32°F) is October 9. 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 80751?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 161 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.