Frost dates for 83213Arco, ID
The average last spring frost in Arco is May 22 and the average first fall frost is September 22, giving a typical growing season of about 119 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 22
- Average first fall frost
- Sep 22
- Growing season
- 119 days
Safer after Jun 9 (1-in-10 risk)
Possible by Sep 4 (1-in-10 risk)
Last frost typically in 201 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 22 · Jun 7 · Jun 28 | Aug 25 · Sep 10 · Sep 26 | 92 days | 100% |
| Frost / freeze (32°F) | May 5 · May 22 · Jun 9 | Sep 4 · Sep 22 · Oct 7 | 119 days | 100% |
| Hard freeze (28°F) | Apr 20 · May 6 · May 24 | Sep 16 · Oct 3 · Oct 19 | 146 days | 100% |
Planting calendar for Arco
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 21 – Jun 27 |
| Tomatoes | Transplant outdoors | Jun 7 – Jun 2 |
| Peppers | Start seeds indoors | Apr 21 – May 22 |
| Peppers | Transplant outdoors | Jun 21 – Jul 22 |
| Eggplant | Start seeds indoors | May 8 – Jun 6 |
| Eggplant | Transplant outdoors | Jun 21 – Jul 22 |
| Cucumbers | Sow outdoors | Jun 21 – Jun 12 |
| Summer squash | Sow outdoors | Jun 7 – Jul 22 |
| Winter squash & pumpkins | Sow outdoors | Jun 21 – Jul 22 |
| Snap beans | Sow outdoors | Jun 7 – Jul 5 |
| Sweet corn | Sow outdoors | Jun 7 – Jun 2 |
| Watermelon & cantaloupe | Sow outdoors | Jun 21 – Jul 22 |
| Okra | Sow outdoors | Jun 14 – Jul 7 |
| Peas | Sow outdoors (spring) | Apr 21 – Jun 6 |
| Potatoes | Plant outdoors (spring) | Apr 21 – Jun 21 |
| Onions | Start seeds indoors (spring) | Mar 10 – Apr 6 |
| Onions | Transplant outdoors (spring) | May 8 – Jun 6 |
| Broccoli | Start seeds indoors (spring) | Apr 3 – May 7 |
| Broccoli | Transplant outdoors (spring) | May 8 – Jun 6 |
| Broccoli | Start seeds indoors (fall) | May 23 – Jun 2 |
| Broccoli | Transplant outdoors (fall) | Jun 22 – Jul 3 |
| Cabbage | Start seeds indoors (spring) | Mar 24 – Apr 21 |
| Cabbage | Transplant outdoors (spring) | Apr 21 – May 22 |
| Cabbage | Start seeds indoors (fall) | May 13 – Jun 12 |
| Cabbage | Transplant outdoors (fall) | Jun 12 – Jul 13 |
| Leaf lettuce | Sow outdoors (spring) | Apr 21 – Jul 7 |
| Leaf lettuce | Sow outdoors (fall) | Jun 12 – Jul 29 |
| Spinach | Sow outdoors (spring) | Apr 14 – May 28 |
| Spinach | Sow outdoors (fall) | Jun 29 – Aug 3 |
| Radishes | Sow outdoors (spring) | Apr 21 – Jun 11 |
| Radishes | Sow outdoors (fall) | Jun 12 – Aug 13 |
| Kale | Sow outdoors (spring) | May 8 – May 28 |
| Kale | Sow outdoors (fall) | Jun 5 – Jul 13 |
| Carrots | Sow outdoors (spring) | May 22 – Jul 7 |
| Carrots | Sow outdoors (fall) | May 13 – Jun 28 |
| Garlic | Plant outdoors (fall) | Sep 12 – Oct 13 |
Where these dates come from
ZIP code 83213 is matched to the NOAA station Arco, ID, 1.4 km away, at 5,325 ft elevation (0 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Arco, ID (used) | 5,325 ft | May 22 | Sep 22 |
| Arco 17 Sw, ID | 5,920 ft | May 24 | Oct 1 |
| Craters Of The Moon, ID | 5,914 ft | Jun 19 | Sep 9 |
| Howe, ID | 4,820 ft | May 24 | Sep 14 |
Frost dates near Arco
- Moore, ID 83255 · last Jun 14, first Sep 8
- Howe, ID 83244 · last May 24, first Sep 14
- Mackay, ID 83251 · last Jun 1, first Sep 20
- Atomic City, ID 83215 · last Jun 11, first Sep 6
- Carey, ID 83320 · last Jun 16, first Sep 9
- Monteview, ID 83435 · last Jun 12, first Sep 7
- Picabo, ID 83348 · last Jun 16, first Sep 9
- Terreton, ID 83450 · last Jun 3, first Sep 11
Frequently asked questions
- When is the last frost in Arco, ID?
- For ZIP code 83213, the average last spring frost (32°F) is May 22, based on NOAA 1991-2020 climate normals for the Arco, ID weather station. There is a 1-in-10 chance of a frost after June 9.
- When is the first frost in Arco, ID?
- The average first fall frost (32°F) is September 22. There is a 1-in-10 chance of frost by September 4, so tender plants are at risk from that point on.
- How long is the growing season in 83213?
- 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.