Frost dates for 84521Elmo, UT
The average last spring frost in Elmo is May 18 and the average first fall frost is September 27, giving a typical growing season of about 128 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 18
- Average first fall frost
- Sep 27
- Growing season
- 128 days
Safer after Jun 8 (1-in-10 risk)
Possible by Sep 14 (1-in-10 risk)
Last frost typically in 203 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 19 · Jun 3 · Jun 19 | Sep 4 · Sep 18 · Sep 28 | 105 days | 100% |
| Frost / freeze (32°F) | May 4 · May 18 · Jun 8 | Sep 14 · Sep 27 · Oct 9 | 128 days | 100% |
| Hard freeze (28°F) | Apr 22 · May 4 · May 20 | Sep 25 · Oct 5 · Oct 20 | 153 days | 100% |
Planting calendar for Elmo
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 17 – Jun 23 |
| Tomatoes | Transplant outdoors | Jun 3 – Jun 7 |
| Peppers | Start seeds indoors | Apr 17 – May 18 |
| Peppers | Transplant outdoors | Jun 17 – Jul 18 |
| Eggplant | Start seeds indoors | May 4 – Jun 2 |
| Eggplant | Transplant outdoors | Jun 17 – Jul 18 |
| Cucumbers | Sow outdoors | Jun 17 – Jun 17 |
| Summer squash | Sow outdoors | Jun 3 – Jul 18 |
| Winter squash & pumpkins | Sow outdoors | Jun 17 – Jul 18 |
| Snap beans | Sow outdoors | Jun 3 – Jul 10 |
| Sweet corn | Sow outdoors | Jun 3 – Jun 7 |
| Watermelon & cantaloupe | Sow outdoors | Jun 17 – Jul 18 |
| Okra | Sow outdoors | Jun 10 – Jul 3 |
| Peas | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Potatoes | Plant outdoors (spring) | Apr 17 – Jun 17 |
| Onions | Start seeds indoors (spring) | Mar 6 – Apr 2 |
| Onions | Transplant outdoors (spring) | May 4 – Jun 2 |
| Broccoli | Start seeds indoors (spring) | Mar 30 – May 3 |
| Broccoli | Transplant outdoors (spring) | May 4 – Jun 2 |
| Broccoli | Start seeds indoors (fall) | May 28 – Jun 7 |
| Broccoli | Transplant outdoors (fall) | Jun 27 – Jul 8 |
| Cabbage | Start seeds indoors (spring) | Mar 20 – Apr 17 |
| Cabbage | Transplant outdoors (spring) | Apr 17 – May 18 |
| Cabbage | Start seeds indoors (fall) | May 18 – Jun 17 |
| Cabbage | Transplant outdoors (fall) | Jun 17 – Jul 18 |
| Leaf lettuce | Sow outdoors (spring) | Apr 17 – Jul 3 |
| Leaf lettuce | Sow outdoors (fall) | Jun 17 – Aug 3 |
| Spinach | Sow outdoors (spring) | Apr 10 – May 24 |
| Spinach | Sow outdoors (fall) | Jul 4 – Aug 8 |
| Radishes | Sow outdoors (spring) | Apr 17 – Jun 7 |
| Radishes | Sow outdoors (fall) | Jun 17 – Aug 18 |
| Kale | Sow outdoors (spring) | May 4 – May 24 |
| Kale | Sow outdoors (fall) | Jun 10 – Jul 18 |
| Carrots | Sow outdoors (spring) | May 18 – Jul 3 |
| Carrots | Sow outdoors (fall) | May 18 – Jul 3 |
| Garlic | Plant outdoors (fall) | Sep 17 – Oct 18 |
Where these dates come from
ZIP code 84521 is matched to the NOAA station Castle Dale, UT, 27.9 km away, at 5,629 ft elevation (21 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Castle Dale, UT (used) | 5,629 ft | May 18 | Sep 27 |
| Wellington 3 E, UT | 5,400 ft | May 27 | Sep 26 |
| Price Carbon Co Ap, UT | 5,921 ft | May 3 | Oct 12 |
| Sunnyside City, UT | 6,511 ft | Apr 26 | Oct 25 |
Frost dates near Elmo
- Cleveland, UT 84518 · last May 18, first Sep 27
- Huntington, UT 84528 · last May 18, first Sep 27
- Wellington, UT 84542 · last May 27, first Sep 26
- Price, UT 84501 · last May 3, first Oct 12
- Castle Dale, UT 84513 · last May 18, first Sep 27
- Orangeville, UT 84537 · last May 18, first Sep 27
- Helper, UT 84526 · last May 3, first Oct 12
- Kenilworth, UT 84529 · last May 3, first Oct 12
Frequently asked questions
- When is the last frost in Elmo, UT?
- For ZIP code 84521, the average last spring frost (32°F) is May 18, based on NOAA 1991-2020 climate normals for the Castle Dale, UT weather station. There is a 1-in-10 chance of a frost after June 8.
- When is the first frost in Elmo, UT?
- The average first fall frost (32°F) is September 27. There is a 1-in-10 chance of frost by September 14, so tender plants are at risk from that point on.
- How long is the growing season in 84521?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 128 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.