Frost dates for 84017Coalville, UT
The average last spring frost in Coalville is May 29 and the average first fall frost is September 25, giving a typical growing season of about 117 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 29
- Average first fall frost
- Sep 25
- Growing season
- 117 days
Safer after Jun 14 (1-in-10 risk)
Possible by Sep 12 (1-in-10 risk)
Last frost typically in 214 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) | May 26 · Jun 10 · Jun 27 | Sep 3 · Sep 15 · Sep 27 | 94 days | 100% |
| Frost / freeze (32°F) | May 12 · May 29 · Jun 14 | Sep 12 · Sep 25 · Oct 9 | 117 days | 100% |
| Hard freeze (28°F) | Apr 25 · May 12 · Jun 1 | Sep 23 · Oct 6 · Oct 21 | 146 days | 100% |
Planting calendar for Coalville
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 | Apr 28 – Jul 4 |
| Tomatoes | Transplant outdoors | Jun 14 – Jun 5 |
| Peppers | Start seeds indoors | Apr 28 – May 29 |
| Peppers | Transplant outdoors | Jun 28 – Jul 29 |
| Eggplant | Start seeds indoors | May 15 – Jun 13 |
| Eggplant | Transplant outdoors | Jun 28 – Jul 29 |
| Cucumbers | Sow outdoors | Jun 28 – Jun 15 |
| Summer squash | Sow outdoors | Jun 14 – Jul 29 |
| Winter squash & pumpkins | Sow outdoors | Jun 28 – Jul 29 |
| Snap beans | Sow outdoors | Jun 14 – Jul 8 |
| Sweet corn | Sow outdoors | Jun 14 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 28 – Jul 29 |
| Okra | Sow outdoors | Jun 21 – Jul 14 |
| Peas | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Potatoes | Plant outdoors (spring) | Apr 28 – Jun 28 |
| Onions | Start seeds indoors (spring) | Mar 17 – Apr 13 |
| Onions | Transplant outdoors (spring) | May 15 – Jun 13 |
| Broccoli | Start seeds indoors (spring) | Apr 10 – May 14 |
| Broccoli | Transplant outdoors (spring) | May 15 – Jun 13 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 31 – Apr 28 |
| Cabbage | Transplant outdoors (spring) | Apr 28 – May 29 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 28 – Jul 14 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 21 – Jun 4 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 28 – Jun 18 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | May 15 – Jun 4 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 29 – Jul 14 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 84017 is matched to the NOAA station Park City, UT, 25.7 km away, at 6,900 ft elevation (380 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Park City, UT (used) | 6,900 ft | May 29 | Sep 25 |
| Wanship Dam, UT | 5,940 ft | Jun 11 | Sep 12 |
| Coalville, UT | 5,550 ft | Jun 7 | Sep 12 |
| Echo Dam, UT | 5,470 ft | May 30 | Sep 18 |
Frost dates near Coalville
- Peoa, UT 84061 · last Jun 11, first Sep 12
- Oakley, UT 84055 · last May 29, first Sep 25
- Echo, UT 84024 · last May 30, first Sep 18
- Kamas, UT 84036 · last Jun 5, first Sep 17
- Park City, UT 84098 · last May 29, first Sep 25
- Henefer, UT 84033 · last May 30, first Sep 18
- Croydon, UT 84018 · last May 30, first Sep 18
- Salt Lake City, UT 84158 · last May 7, first Oct 14
Frequently asked questions
- When is the last frost in Coalville, UT?
- For ZIP code 84017, the average last spring frost (32°F) is May 29, based on NOAA 1991-2020 climate normals for the Park City, UT weather station. There is a 1-in-10 chance of a frost after June 14.
- When is the first frost in Coalville, UT?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 12, so tender plants are at risk from that point on.
- How long is the growing season in 84017?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 117 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.