Frost dates for 80451Hot Sulphur Springs, CO
The average last spring frost in Hot Sulphur Springs is June 12 and the average first fall frost is September 10, giving a typical growing season of about 89 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 12
- Average first fall frost
- Sep 10
- Growing season
- 89 days
Safer after Jun 25 (1-in-10 risk)
Possible by Aug 31 (1-in-10 risk)
Last frost typically in 228 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) | Jun 16 · Jun 28 · Jul 14 | Aug 13 · Aug 29 · Sep 9 | 59 days | 100% |
| Frost / freeze (32°F) | May 31 · Jun 12 · Jun 25 | Aug 31 · Sep 10 · Sep 21 | 89 days | 100% |
| Hard freeze (28°F) | May 13 · May 26 · Jun 9 | Sep 8 · Sep 20 · Oct 3 | 115 days | 100% |
Planting calendar for Hot Sulphur Springs
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 12 – Jul 18 |
| Tomatoes | Transplant outdoors | Jun 28 – May 21 |
| Peppers | Start seeds indoors | May 12 – Jun 12 |
| Peppers | Transplant outdoors | Jul 12 – Aug 12 |
| Eggplant | Start seeds indoors | May 29 – Jun 27 |
| Eggplant | Transplant outdoors | Jul 12 – Aug 12 |
| Cucumbers | Sow outdoors | Jul 12 – May 31 |
| Summer squash | Sow outdoors | Jun 28 – Aug 12 |
| Winter squash & pumpkins | Sow outdoors | Jul 12 – Aug 12 |
| Snap beans | Sow outdoors | Jun 28 – Jun 23 |
| Sweet corn | Sow outdoors | Jun 28 – May 21 |
| Watermelon & cantaloupe | Sow outdoors | Jul 12 – Aug 12 |
| Okra | Sow outdoors | Jul 5 – Jul 28 |
| Peas | Sow outdoors (spring) | May 12 – Jun 27 |
| Potatoes | Plant outdoors (spring) | May 12 – Jul 12 |
| Onions | Start seeds indoors (spring) | Mar 31 – Apr 27 |
| Onions | Transplant outdoors (spring) | May 29 – Jun 27 |
| Broccoli | Start seeds indoors (spring) | Apr 24 – May 28 |
| Broccoli | Transplant outdoors (spring) | May 29 – Jun 27 |
| Broccoli | Start seeds indoors (fall) | May 11 – May 21 |
| Broccoli | Transplant outdoors (fall) | Jun 10 – Jun 21 |
| Cabbage | Start seeds indoors (spring) | Apr 14 – May 12 |
| Cabbage | Transplant outdoors (spring) | May 12 – Jun 12 |
| Cabbage | Start seeds indoors (fall) | May 1 – May 31 |
| Cabbage | Transplant outdoors (fall) | May 31 – Jul 1 |
| Leaf lettuce | Sow outdoors (spring) | May 12 – Jul 28 |
| Leaf lettuce | Sow outdoors (fall) | May 31 – Jul 17 |
| Spinach | Sow outdoors (spring) | May 5 – Jun 18 |
| Spinach | Sow outdoors (fall) | Jun 17 – Jul 22 |
| Radishes | Sow outdoors (spring) | May 12 – Jul 2 |
| Radishes | Sow outdoors (fall) | May 31 – Aug 1 |
| Kale | Sow outdoors (spring) | May 29 – Jun 18 |
| Kale | Sow outdoors (fall) | May 24 – Jul 1 |
| Carrots | Sow outdoors (spring) | Jun 12 – Jul 28 |
| Carrots | Sow outdoors (fall) | May 1 – Jun 16 |
| Garlic | Plant outdoors (fall) | Aug 31 – Oct 1 |
Where these dates come from
ZIP code 80451 is matched to the NOAA station Williams Fork Dam, CO, 12.1 km away, at 7,618 ft elevation (331 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Williams Fork Dam, CO (used) | 7,618 ft | Jun 12 | Sep 10 |
| Grand Lake 6 Ssw, CO | 8,288 ft | Jun 13 | Sep 7 |
| Kremmling, CO | 7,460 ft | Jun 14 | Sep 5 |
| Fraser, CO | 8,560 ft | — | — |
Frost dates near Hot Sulphur Springs
- Granby, CO 80446 · last Jun 13, first Sep 7
- Parshall, CO 80468 · last —, first —
- Tabernash, CO 80478 · last —, first —
- Grand Lake, CO 80447 · last —, first —
- Fraser, CO 80442 · last —, first —
- Kremmling, CO 80459 · last Jun 14, first Sep 5
- Winter Park, CO 80482 · last Jun 21, first Sep 2
- Silverthorne, CO 80498 · last —, first —
Frequently asked questions
- When is the last frost in Hot Sulphur Springs, CO?
- For ZIP code 80451, the average last spring frost (32°F) is June 12, based on NOAA 1991-2020 climate normals for the Williams Fork Dam, CO weather station. There is a 1-in-10 chance of a frost after June 25.
- When is the first frost in Hot Sulphur Springs, CO?
- The average first fall frost (32°F) is September 10. 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 80451?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 89 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.