Frost dates for 80428Clark, CO
The average last spring frost in Clark is June 9 and the average first fall frost is September 12, giving a typical growing season of about 93 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 9
- Average first fall frost
- Sep 12
- Growing season
- 93 days
Safer after Jun 24 (1-in-10 risk)
Possible by Aug 31 (1-in-10 risk)
Last frost typically in 222 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 25 · Jun 9 · Jun 24 | Aug 31 · Sep 12 · Sep 24 | 93 days | 100% |
| Hard freeze (28°F) | May 2 · May 20 · Jun 6 | Sep 9 · Sep 23 · Oct 6 | 126 days | 100% |
Planting calendar for Clark
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 9 – Jul 15 |
| Tomatoes | Transplant outdoors | Jun 25 – May 23 |
| Peppers | Start seeds indoors | May 9 – Jun 9 |
| Peppers | Transplant outdoors | Jul 9 – Aug 9 |
| Eggplant | Start seeds indoors | May 26 – Jun 24 |
| Eggplant | Transplant outdoors | Jul 9 – Aug 9 |
| Cucumbers | Sow outdoors | Jul 9 – Jun 2 |
| Summer squash | Sow outdoors | Jun 25 – Aug 9 |
| Winter squash & pumpkins | Sow outdoors | Jul 9 – Aug 9 |
| Snap beans | Sow outdoors | Jun 25 – Jun 25 |
| Sweet corn | Sow outdoors | Jun 25 – May 23 |
| Watermelon & cantaloupe | Sow outdoors | Jul 9 – Aug 9 |
| Okra | Sow outdoors | Jul 2 – Jul 25 |
| Peas | Sow outdoors (spring) | May 9 – Jun 24 |
| Potatoes | Plant outdoors (spring) | May 9 – Jul 9 |
| Onions | Start seeds indoors (spring) | Mar 28 – Apr 24 |
| Onions | Transplant outdoors (spring) | May 26 – Jun 24 |
| Broccoli | Start seeds indoors (spring) | Apr 21 – May 25 |
| Broccoli | Transplant outdoors (spring) | May 26 – Jun 24 |
| Broccoli | Start seeds indoors (fall) | May 13 – May 23 |
| Broccoli | Transplant outdoors (fall) | Jun 12 – Jun 23 |
| Cabbage | Start seeds indoors (spring) | Apr 11 – May 9 |
| Cabbage | Transplant outdoors (spring) | May 9 – Jun 9 |
| Cabbage | Start seeds indoors (fall) | May 3 – Jun 2 |
| Cabbage | Transplant outdoors (fall) | Jun 2 – Jul 3 |
| Leaf lettuce | Sow outdoors (spring) | May 9 – Jul 25 |
| Leaf lettuce | Sow outdoors (fall) | Jun 2 – Jul 19 |
| Spinach | Sow outdoors (spring) | May 2 – Jun 15 |
| Spinach | Sow outdoors (fall) | Jun 19 – Jul 24 |
| Radishes | Sow outdoors (spring) | May 9 – Jun 29 |
| Radishes | Sow outdoors (fall) | Jun 2 – Aug 3 |
| Kale | Sow outdoors (spring) | May 26 – Jun 15 |
| Kale | Sow outdoors (fall) | May 26 – Jul 3 |
| Carrots | Sow outdoors (spring) | Jun 9 – Jul 25 |
| Carrots | Sow outdoors (fall) | May 3 – Jun 18 |
| Garlic | Plant outdoors (fall) | Sep 2 – Oct 3 |
Where these dates come from
ZIP code 80428 is matched to the NOAA station Steamboat Springs, CO, 27.8 km away, at 6,866 ft elevation (749 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Steamboat Springs, CO (used) | 6,866 ft | Jun 9 | Sep 12 |
| Hayden, CO | 6,467 ft | Jun 1 | Sep 20 |
| Spicer, CO | 8,385 ft | — | — |
| Walden, CO | 8,056 ft | — | — |
Frost dates near Clark
- Steamboat Springs, CO 80487 · last Jun 9, first Sep 12
- Hayden, CO 81639 · last Jun 1, first Sep 20
- Coalmont, CO 80430 · last —, first —
- Slater, CO 81653 · last Jun 1, first Sep 18
- Oak Creek, CO 80467 · last Jun 14, first Sep 11
- Cowdrey, CO 80434 · last —, first —
- Walden, CO 80480 · last —, first —
- Encampment, WY 82325 · last May 28, first Sep 13
Frequently asked questions
- When is the last frost in Clark, CO?
- For ZIP code 80428, the average last spring frost (32°F) is June 9, based on NOAA 1991-2020 climate normals for the Steamboat Springs, CO weather station. There is a 1-in-10 chance of a frost after June 24.
- When is the first frost in Clark, CO?
- The average first fall frost (32°F) is September 12. There is a 1-in-10 chance of frost by August 31, so tender plants are at risk from that point on.
- How long is the growing season in 80428?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 93 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.