Frost dates for 84710Alton, UT
The average last spring frost in Alton is June 1 and the average first fall frost is September 30, giving a typical growing season of about 120 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 1
- Average first fall frost
- Sep 30
- Growing season
- 120 days
Safer after Jun 15 (1-in-10 risk)
Possible by Sep 16 (1-in-10 risk)
Last frost typically in 217 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 30 · Jun 11 · Jun 24 | Sep 7 · Sep 20 · Oct 1 | 99 days | 100% |
| Frost / freeze (32°F) | May 16 · Jun 1 · Jun 15 | Sep 16 · Sep 30 · Oct 12 | 120 days | 100% |
| Hard freeze (28°F) | Apr 29 · May 17 · Jun 4 | Sep 27 · Oct 11 · Oct 24 | 147 days | 100% |
Planting calendar for Alton
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 | May 1 – Jul 7 |
| Tomatoes | Transplant outdoors | Jun 17 – Jun 10 |
| Peppers | Start seeds indoors | May 1 – Jun 1 |
| Peppers | Transplant outdoors | Jul 1 – Aug 1 |
| Eggplant | Start seeds indoors | May 18 – Jun 16 |
| Eggplant | Transplant outdoors | Jul 1 – Aug 1 |
| Cucumbers | Sow outdoors | Jul 1 – Jun 20 |
| Summer squash | Sow outdoors | Jun 17 – Aug 1 |
| Winter squash & pumpkins | Sow outdoors | Jul 1 – Aug 1 |
| Snap beans | Sow outdoors | Jun 17 – Jul 13 |
| Sweet corn | Sow outdoors | Jun 17 – Jun 10 |
| Watermelon & cantaloupe | Sow outdoors | Jul 1 – Aug 1 |
| Okra | Sow outdoors | Jun 24 – Jul 17 |
| Peas | Sow outdoors (spring) | May 1 – Jun 16 |
| Potatoes | Plant outdoors (spring) | May 1 – Jul 1 |
| Onions | Start seeds indoors (spring) | Mar 20 – Apr 16 |
| Onions | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (spring) | Apr 13 – May 17 |
| Broccoli | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (fall) | May 31 – Jun 10 |
| Broccoli | Transplant outdoors (fall) | Jun 30 – Jul 11 |
| Cabbage | Start seeds indoors (spring) | Apr 3 – May 1 |
| Cabbage | Transplant outdoors (spring) | May 1 – Jun 1 |
| Cabbage | Start seeds indoors (fall) | May 21 – Jun 20 |
| Cabbage | Transplant outdoors (fall) | Jun 20 – Jul 21 |
| Leaf lettuce | Sow outdoors (spring) | May 1 – Jul 17 |
| Leaf lettuce | Sow outdoors (fall) | Jun 20 – Aug 6 |
| Spinach | Sow outdoors (spring) | Apr 24 – Jun 7 |
| Spinach | Sow outdoors (fall) | Jul 7 – Aug 11 |
| Radishes | Sow outdoors (spring) | May 1 – Jun 21 |
| Radishes | Sow outdoors (fall) | Jun 20 – Aug 21 |
| Kale | Sow outdoors (spring) | May 18 – Jun 7 |
| Kale | Sow outdoors (fall) | Jun 13 – Jul 21 |
| Carrots | Sow outdoors (spring) | Jun 1 – Jul 17 |
| Carrots | Sow outdoors (fall) | May 21 – Jul 6 |
| Garlic | Plant outdoors (fall) | Sep 20 – Oct 21 |
Where these dates come from
ZIP code 84710 is matched to the NOAA station Alton, UT, 6.7 km away, at 7,098 ft elevation (448 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Alton, UT (used) | 7,098 ft | Jun 1 | Sep 30 |
| Hatch, UT | 6,893 ft | Jun 19 | Sep 13 |
| Orderville, UT | 5,460 ft | May 15 | Oct 8 |
| Cedar Breaks Nm, UT | 10,373 ft | Jun 11 | Oct 3 |
Frost dates near Alton
- Duck Creek Village, UT 84762 · last Jun 21, first Sep 12
- Glendale, UT 84729 · last May 15, first Oct 8
- Hatch, UT 84735 · last Jun 19, first Sep 13
- Orderville, UT 84758 · last May 15, first Oct 8
- Mount Carmel, UT 84755 · last May 15, first Oct 8
- Brian Head, UT 84719 · last Jun 21, first Sep 12
- Bryce, UT 84764 · last May 23, first Sep 27
- Panguitch, UT 84759 · last Jun 12, first Sep 12
Frequently asked questions
- When is the last frost in Alton, UT?
- For ZIP code 84710, the average last spring frost (32°F) is June 1, based on NOAA 1991-2020 climate normals for the Alton, UT weather station. There is a 1-in-10 chance of a frost after June 15.
- When is the first frost in Alton, UT?
- The average first fall frost (32°F) is September 30. There is a 1-in-10 chance of frost by September 16, so tender plants are at risk from that point on.
- How long is the growing season in 84710?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 120 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.