Frost dates for 84539Sunnyside, UT
The average last spring frost in Sunnyside is May 5 and the average first fall frost is October 15, giving a typical growing season of about 159 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 5
- Average first fall frost
- Oct 15
- Growing season
- 159 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 30 (1-in-10 risk)
Last frost typically in 190 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 4 · May 22 · Jun 9 | Sep 16 · Oct 2 · Oct 19 | 133 days | 100% |
| Frost / freeze (32°F) | Apr 21 · May 5 · May 26 | Sep 30 · Oct 15 · Nov 1 | 159 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 24 · May 12 | Oct 9 · Oct 25 · Nov 10 | 181 days | 100% |
Planting calendar for Sunnyside
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 4 – Jun 10 |
| Tomatoes | Transplant outdoors | May 21 – Jun 25 |
| Peppers | Start seeds indoors | Apr 4 – May 5 |
| Peppers | Transplant outdoors | Jun 4 – Jul 5 |
| Eggplant | Start seeds indoors | Apr 21 – May 20 |
| Eggplant | Transplant outdoors | Jun 4 – Jul 5 |
| Cucumbers | Sow outdoors | Jun 4 – Jul 5 |
| Summer squash | Sow outdoors | May 21 – Jul 5 |
| Winter squash & pumpkins | Sow outdoors | Jun 4 – Jul 5 |
| Snap beans | Sow outdoors | May 21 – Jul 28 |
| Sweet corn | Sow outdoors | May 21 – Jun 25 |
| Watermelon & cantaloupe | Sow outdoors | Jun 4 – Jul 5 |
| Okra | Sow outdoors | May 28 – Jun 20 |
| Peas | Sow outdoors (spring) | Apr 4 – May 20 |
| Potatoes | Plant outdoors (spring) | Apr 4 – Jun 4 |
| Onions | Start seeds indoors (spring) | Feb 21 – Mar 20 |
| Onions | Transplant outdoors (spring) | Apr 21 – May 20 |
| Broccoli | Start seeds indoors (spring) | Mar 17 – Apr 20 |
| Broccoli | Transplant outdoors (spring) | Apr 21 – May 20 |
| Broccoli | Start seeds indoors (fall) | Jun 15 – Jun 25 |
| Broccoli | Transplant outdoors (fall) | Jul 15 – Jul 26 |
| Cabbage | Start seeds indoors (spring) | Mar 7 – Apr 4 |
| Cabbage | Transplant outdoors (spring) | Apr 4 – May 5 |
| Cabbage | Start seeds indoors (fall) | Jun 5 – Jul 5 |
| Cabbage | Transplant outdoors (fall) | Jul 5 – Aug 5 |
| Leaf lettuce | Sow outdoors (spring) | Apr 4 – Jun 20 |
| Leaf lettuce | Sow outdoors (fall) | Jul 5 – Aug 21 |
| Spinach | Sow outdoors (spring) | Mar 28 – May 11 |
| Spinach | Sow outdoors (fall) | Jul 22 – Aug 26 |
| Radishes | Sow outdoors (spring) | Apr 4 – May 25 |
| Radishes | Sow outdoors (fall) | Jul 5 – Sep 5 |
| Kale | Sow outdoors (spring) | Apr 21 – May 11 |
| Kale | Sow outdoors (fall) | Jun 28 – Aug 5 |
| Carrots | Sow outdoors (spring) | May 5 – Jun 20 |
| Carrots | Sow outdoors (fall) | Jun 5 – Jul 21 |
| Garlic | Plant outdoors (fall) | Oct 5 – Nov 5 |
Where these dates come from
ZIP code 84539 is matched to the NOAA station Sunnyside City Ctr, UT, 0.2 km away, at 6,530 ft elevation (11 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Sunnyside City Ctr, UT (used) | 6,530 ft | May 5 | Oct 15 |
| Sunnyside City, UT | 6,511 ft | Apr 26 | Oct 25 |
| Wellington 3 E, UT | 5,400 ft | May 27 | Sep 26 |
| Price Carbon Co Ap, UT | 5,921 ft | May 3 | Oct 12 |
Frost dates near Sunnyside
- East Carbon, UT 84520 · last May 5, first Oct 15
- Wellington, UT 84542 · last May 27, first Sep 26
- Price, UT 84501 · last May 3, first Oct 12
- Kenilworth, UT 84529 · last May 3, first Oct 12
- Elmo, UT 84521 · last May 18, first Sep 27
- Helper, UT 84526 · last May 3, first Oct 12
- Cleveland, UT 84518 · last May 18, first Sep 27
- Huntington, UT 84528 · last May 18, first Sep 27
Frequently asked questions
- When is the last frost in Sunnyside, UT?
- For ZIP code 84539, the average last spring frost (32°F) is May 5, based on NOAA 1991-2020 climate normals for the Sunnyside City Ctr, UT weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Sunnyside, UT?
- The average first fall frost (32°F) is October 15. There is a 1-in-10 chance of frost by September 30, so tender plants are at risk from that point on.
- How long is the growing season in 84539?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 159 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.