Frost dates for 84021Duchesne, UT
The average last spring frost in Duchesne is May 6 and the average first fall frost is October 5, giving a typical growing season of about 150 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 6
- Average first fall frost
- Oct 5
- Growing season
- 150 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 24 (1-in-10 risk)
Last frost typically in 186 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 7 · May 22 · Jun 10 | Sep 13 · Sep 26 · Oct 7 | 125 days | 100% |
| Frost / freeze (32°F) | Apr 22 · May 6 · May 26 | Sep 24 · Oct 5 · Oct 18 | 150 days | 100% |
| Hard freeze (28°F) | Apr 9 · Apr 22 · May 7 | Oct 2 · Oct 16 · Oct 28 | 174 days | 100% |
Planting calendar for Duchesne
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 5 – Jun 11 |
| Tomatoes | Transplant outdoors | May 22 – Jun 15 |
| Peppers | Start seeds indoors | Apr 5 – May 6 |
| Peppers | Transplant outdoors | Jun 5 – Jul 6 |
| Eggplant | Start seeds indoors | Apr 22 – May 21 |
| Eggplant | Transplant outdoors | Jun 5 – Jul 6 |
| Cucumbers | Sow outdoors | Jun 5 – Jun 25 |
| Summer squash | Sow outdoors | May 22 – Jul 6 |
| Winter squash & pumpkins | Sow outdoors | Jun 5 – Jul 6 |
| Snap beans | Sow outdoors | May 22 – Jul 18 |
| Sweet corn | Sow outdoors | May 22 – Jun 15 |
| Watermelon & cantaloupe | Sow outdoors | Jun 5 – Jul 6 |
| Okra | Sow outdoors | May 29 – Jun 21 |
| Peas | Sow outdoors (spring) | Apr 5 – May 21 |
| Potatoes | Plant outdoors (spring) | Apr 5 – Jun 5 |
| Onions | Start seeds indoors (spring) | Feb 22 – Mar 21 |
| Onions | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (spring) | Mar 18 – Apr 21 |
| Broccoli | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (fall) | Jun 5 – Jun 15 |
| Broccoli | Transplant outdoors (fall) | Jul 5 – Jul 16 |
| Cabbage | Start seeds indoors (spring) | Mar 8 – Apr 5 |
| Cabbage | Transplant outdoors (spring) | Apr 5 – May 6 |
| Cabbage | Start seeds indoors (fall) | May 26 – Jun 25 |
| Cabbage | Transplant outdoors (fall) | Jun 25 – Jul 26 |
| Leaf lettuce | Sow outdoors (spring) | Apr 5 – Jun 21 |
| Leaf lettuce | Sow outdoors (fall) | Jun 25 – Aug 11 |
| Spinach | Sow outdoors (spring) | Mar 29 – May 12 |
| Spinach | Sow outdoors (fall) | Jul 12 – Aug 16 |
| Radishes | Sow outdoors (spring) | Apr 5 – May 26 |
| Radishes | Sow outdoors (fall) | Jun 25 – Aug 26 |
| Kale | Sow outdoors (spring) | Apr 22 – May 12 |
| Kale | Sow outdoors (fall) | Jun 18 – Jul 26 |
| Carrots | Sow outdoors (spring) | May 6 – Jun 21 |
| Carrots | Sow outdoors (fall) | May 26 – Jul 11 |
| Garlic | Plant outdoors (fall) | Sep 25 – Oct 26 |
Where these dates come from
ZIP code 84021 is matched to the NOAA station Duchesne, UT, 0.9 km away, at 5,551 ft elevation (32 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Duchesne, UT (used) | 5,551 ft | May 6 | Oct 5 |
| Altamont, UT | 6,456 ft | May 31 | Sep 23 |
| Myton, UT | 5,085 ft | May 7 | Oct 5 |
| Roosevelt Radio, UT | 5,014 ft | May 23 | Sep 22 |
Frost dates near Duchesne
- Talmage, UT 84073 · last May 31, first Sep 23
- Altamont, UT 84001 · last May 31, first Sep 23
- Mountain Home, UT 84051 · last May 31, first Sep 23
- Bluebell, UT 84007 · last May 31, first Sep 23
- Altonah, UT 84002 · last May 31, first Sep 23
- Myton, UT 84052 · last May 7, first Oct 5
- Tabiona, UT 84072 · last May 31, first Sep 23
- Fruitland, UT 84027 · last Jun 15, first Sep 12
Frequently asked questions
- When is the last frost in Duchesne, UT?
- For ZIP code 84021, the average last spring frost (32°F) is May 6, based on NOAA 1991-2020 climate normals for the Duchesne, UT weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Duchesne, UT?
- The average first fall frost (32°F) is October 5. There is a 1-in-10 chance of frost by September 24, so tender plants are at risk from that point on.
- How long is the growing season in 84021?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 150 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.