Frost dates for 83440Rexburg, ID
The average last spring frost in Rexburg is May 12 and the average first fall frost is September 24, giving a typical growing season of about 132 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Sep 24
- Growing season
- 132 days
Safer after Jun 2 (1-in-10 risk)
Possible by Sep 6 (1-in-10 risk)
Last frost typically in 197 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 16 · Jun 4 · Jun 22 | Aug 28 · Sep 11 · Sep 25 | 98 days | 100% |
| Frost / freeze (32°F) | Apr 29 · May 12 · Jun 2 | Sep 6 · Sep 24 · Oct 8 | 132 days | 100% |
| Hard freeze (28°F) | Apr 12 · Apr 30 · May 14 | Sep 20 · Oct 7 · Oct 21 | 161 days | 100% |
Planting calendar for Rexburg
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 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 4 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 14 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 7 |
| Sweet corn | Sow outdoors | May 28 – Jun 4 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | May 25 – Jun 4 |
| Broccoli | Transplant outdoors (fall) | Jun 24 – Jul 5 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 15 – Jun 14 |
| Cabbage | Transplant outdoors (fall) | Jun 14 – Jul 15 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 14 – Jul 31 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 1 – Aug 5 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 14 – Aug 15 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 7 – Jul 15 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 15 – Jun 30 |
| Garlic | Plant outdoors (fall) | Sep 14 – Oct 15 |
Where these dates come from
ZIP code 83440 is matched to the NOAA station Rexburg Byu Idaho, ID, 0.2 km away, at 5,005 ft elevation (48 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Rexburg Byu Idaho, ID (used) | 5,005 ft | May 12 | Sep 24 |
| Rexburg Madison Co Ap, ID | 4,858 ft | May 15 | Sep 23 |
| Sugar City, ID | 4,925 ft | May 29 | Sep 13 |
| Rigby, ID | 4,856 ft | May 9 | Oct 5 |
Frost dates near Rexburg
- Rexburg, ID 83460 · last May 15, first Sep 23
- Sugar City, ID 83448 · last May 15, first Sep 23
- Teton, ID 83451 · last May 17, first Sep 22
- Parker, ID 83438 · last May 17, first Sep 22
- Newdale, ID 83436 · last May 17, first Sep 22
- Rigby, ID 83442 · last May 9, first Oct 5
- Menan, ID 83434 · last May 15, first Sep 23
- Saint Anthony, ID 83445 · last May 17, first Sep 22
Frequently asked questions
- When is the last frost in Rexburg, ID?
- For ZIP code 83440, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Rexburg Byu Idaho, ID weather station. There is a 1-in-10 chance of a frost after June 2.
- When is the first frost in Rexburg, ID?
- The average first fall frost (32°F) is September 24. There is a 1-in-10 chance of frost by September 6, so tender plants are at risk from that point on.
- How long is the growing season in 83440?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 132 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.