Frost dates for 83442Rigby, ID
The average last spring frost in Rigby is May 9 and the average first fall frost is October 5, giving a typical growing season of about 148 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 9
- Average first fall frost
- Oct 5
- Growing season
- 148 days
Safer after May 25 (1-in-10 risk)
Possible by Sep 21 (1-in-10 risk)
Last frost typically in 187 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 10 · May 26 · Jun 14 | Sep 9 · Sep 24 · Oct 6 | 118 days | 100% |
| Frost / freeze (32°F) | Apr 27 · May 9 · May 25 | Sep 21 · Oct 5 · Oct 18 | 148 days | 100% |
| Hard freeze (28°F) | Apr 12 · Apr 28 · May 11 | Oct 2 · Oct 16 · Oct 28 | 170 days | 100% |
Planting calendar for Rigby
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 8 – Jun 14 |
| Tomatoes | Transplant outdoors | May 25 – Jun 15 |
| Peppers | Start seeds indoors | Apr 8 – May 9 |
| Peppers | Transplant outdoors | Jun 8 – Jul 9 |
| Eggplant | Start seeds indoors | Apr 25 – May 24 |
| Eggplant | Transplant outdoors | Jun 8 – Jul 9 |
| Cucumbers | Sow outdoors | Jun 8 – Jun 25 |
| Summer squash | Sow outdoors | May 25 – Jul 9 |
| Winter squash & pumpkins | Sow outdoors | Jun 8 – Jul 9 |
| Snap beans | Sow outdoors | May 25 – Jul 18 |
| Sweet corn | Sow outdoors | May 25 – Jun 15 |
| Watermelon & cantaloupe | Sow outdoors | Jun 8 – Jul 9 |
| Okra | Sow outdoors | Jun 1 – Jun 24 |
| Peas | Sow outdoors (spring) | Apr 8 – May 24 |
| Potatoes | Plant outdoors (spring) | Apr 8 – Jun 8 |
| Onions | Start seeds indoors (spring) | Feb 25 – Mar 24 |
| Onions | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (spring) | Mar 21 – Apr 24 |
| Broccoli | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (fall) | Jun 5 – Jun 15 |
| Broccoli | Transplant outdoors (fall) | Jul 5 – Jul 16 |
| Cabbage | Start seeds indoors (spring) | Mar 11 – Apr 8 |
| Cabbage | Transplant outdoors (spring) | Apr 8 – May 9 |
| Cabbage | Start seeds indoors (fall) | May 26 – Jun 25 |
| Cabbage | Transplant outdoors (fall) | Jun 25 – Jul 26 |
| Leaf lettuce | Sow outdoors (spring) | Apr 8 – Jun 24 |
| Leaf lettuce | Sow outdoors (fall) | Jun 25 – Aug 11 |
| Spinach | Sow outdoors (spring) | Apr 1 – May 15 |
| Spinach | Sow outdoors (fall) | Jul 12 – Aug 16 |
| Radishes | Sow outdoors (spring) | Apr 8 – May 29 |
| Radishes | Sow outdoors (fall) | Jun 25 – Aug 26 |
| Kale | Sow outdoors (spring) | Apr 25 – May 15 |
| Kale | Sow outdoors (fall) | Jun 18 – Jul 26 |
| Carrots | Sow outdoors (spring) | May 9 – Jun 24 |
| Carrots | Sow outdoors (fall) | May 26 – Jul 11 |
| Garlic | Plant outdoors (fall) | Sep 25 – Oct 26 |
Where these dates come from
ZIP code 83442 is matched to the NOAA station Rigby, ID, 1.1 km away, at 4,856 ft elevation (10 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Rigby, ID (used) | 4,856 ft | May 9 | Oct 5 |
| Rexburg Byu Idaho, ID | 5,005 ft | May 12 | Sep 24 |
| Rexburg Madison Co Ap, ID | 4,858 ft | May 15 | Sep 23 |
| Idaho Falls - Kifi, ID | 4,742 ft | May 9 | Oct 1 |
Frost dates near Rigby
- Menan, ID 83434 · last May 15, first Sep 23
- Lewisville, ID 83431 · last May 9, first Oct 1
- Ucon, ID 83454 · last May 9, first Oct 1
- Idaho Falls, ID 83401 · last May 9, first Oct 1
- Iona, ID 83427 · last May 9, first Oct 1
- Rexburg, ID 83440 · last May 12, first Sep 24
- Roberts, ID 83444 · last May 23, first Sep 20
- Sugar City, ID 83448 · last May 15, first Sep 23
Frequently asked questions
- When is the last frost in Rigby, ID?
- For ZIP code 83442, the average last spring frost (32°F) is May 9, based on NOAA 1991-2020 climate normals for the Rigby, ID weather station. There is a 1-in-10 chance of a frost after May 25.
- When is the first frost in Rigby, ID?
- The average first fall frost (32°F) is October 5. There is a 1-in-10 chance of frost by September 21, so tender plants are at risk from that point on.
- How long is the growing season in 83442?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 148 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.