Frost dates for 84646Moroni, UT
The average last spring frost in Moroni is May 26 and the average first fall frost is September 25, giving a typical growing season of about 119 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 26
- Average first fall frost
- Sep 25
- Growing season
- 119 days
Safer after Jun 13 (1-in-10 risk)
Possible by Sep 9 (1-in-10 risk)
Last frost typically in 209 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 27 · Jun 10 · Jun 28 | Sep 1 · Sep 16 · Sep 27 | 94 days | 100% |
| Frost / freeze (32°F) | May 10 · May 26 · Jun 13 | Sep 9 · Sep 25 · Oct 8 | 119 days | 100% |
| Hard freeze (28°F) | Apr 25 · May 10 · May 30 | Sep 21 · Oct 5 · Oct 20 | 147 days | 100% |
Planting calendar for Moroni
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 25 – Jul 1 |
| Tomatoes | Transplant outdoors | Jun 11 – Jun 5 |
| Peppers | Start seeds indoors | Apr 25 – May 26 |
| Peppers | Transplant outdoors | Jun 25 – Jul 26 |
| Eggplant | Start seeds indoors | May 12 – Jun 10 |
| Eggplant | Transplant outdoors | Jun 25 – Jul 26 |
| Cucumbers | Sow outdoors | Jun 25 – Jun 15 |
| Summer squash | Sow outdoors | Jun 11 – Jul 26 |
| Winter squash & pumpkins | Sow outdoors | Jun 25 – Jul 26 |
| Snap beans | Sow outdoors | Jun 11 – Jul 8 |
| Sweet corn | Sow outdoors | Jun 11 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 25 – Jul 26 |
| Okra | Sow outdoors | Jun 18 – Jul 11 |
| Peas | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Potatoes | Plant outdoors (spring) | Apr 25 – Jun 25 |
| Onions | Start seeds indoors (spring) | Mar 14 – Apr 10 |
| Onions | Transplant outdoors (spring) | May 12 – Jun 10 |
| Broccoli | Start seeds indoors (spring) | Apr 7 – May 11 |
| Broccoli | Transplant outdoors (spring) | May 12 – Jun 10 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 28 – Apr 25 |
| Cabbage | Transplant outdoors (spring) | Apr 25 – May 26 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 25 – Jul 11 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 18 – Jun 1 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 25 – Jun 15 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | May 12 – Jun 1 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 26 – Jul 11 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 84646 is matched to the NOAA station Moroni, UT, 0.3 km away, at 5,580 ft elevation (49 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Moroni, UT (used) | 5,580 ft | May 26 | Sep 25 |
| Ephraim, UT | 5,498 ft | May 28 | Sep 20 |
| Levan, UT | 5,298 ft | May 10 | Oct 7 |
| Manti Radio Kmti, UT | 5,498 ft | May 31 | Sep 21 |
Frost dates near Moroni
- Wales, UT 84667 · last May 26, first Sep 25
- Chester, UT 84623 · last May 26, first Sep 25
- Mount Pleasant, UT 84647 · last May 26, first Sep 25
- Fountain Green, UT 84632 · last May 26, first Sep 25
- Spring City, UT 84662 · last May 26, first Sep 25
- Fairview, UT 84629 · last May 26, first Sep 25
- Ephraim, UT 84627 · last May 28, first Sep 20
- Nephi, UT 84648 · last May 6, first Oct 10
Frequently asked questions
- When is the last frost in Moroni, UT?
- For ZIP code 84646, the average last spring frost (32°F) is May 26, based on NOAA 1991-2020 climate normals for the Moroni, UT weather station. There is a 1-in-10 chance of a frost after June 13.
- When is the first frost in Moroni, UT?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 9, so tender plants are at risk from that point on.
- How long is the growing season in 84646?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 119 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.