Frost dates for 83423Dubois, ID
The average last spring frost in Dubois is May 18 and the average first fall frost is September 30, giving a typical growing season of about 132 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 18
- Average first fall frost
- Sep 30
- Growing season
- 132 days
Safer after Jun 9 (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 18 · Jun 5 · Jun 22 | Sep 4 · Sep 18 · Oct 1 | 102 days | 100% |
| Frost / freeze (32°F) | May 3 · May 18 · Jun 9 | Sep 14 · Sep 30 · Oct 16 | 132 days | 100% |
| Hard freeze (28°F) | Apr 16 · May 2 · May 17 | Sep 27 · Oct 12 · Oct 26 | 162 days | 100% |
Planting calendar for Dubois
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 10 |
| 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 20 |
| Summer squash | Sow outdoors | Jun 3 – Jul 18 |
| Winter squash & pumpkins | Sow outdoors | Jun 17 – Jul 18 |
| Snap beans | Sow outdoors | Jun 3 – Jul 13 |
| Sweet corn | Sow outdoors | Jun 3 – Jun 10 |
| 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 31 – Jun 10 |
| Broccoli | Transplant outdoors (fall) | Jun 30 – Jul 11 |
| Cabbage | Start seeds indoors (spring) | Mar 20 – Apr 17 |
| Cabbage | Transplant outdoors (spring) | Apr 17 – May 18 |
| Cabbage | Start seeds indoors (fall) | May 21 – Jun 20 |
| Cabbage | Transplant outdoors (fall) | Jun 20 – Jul 21 |
| Leaf lettuce | Sow outdoors (spring) | Apr 17 – Jul 3 |
| Leaf lettuce | Sow outdoors (fall) | Jun 20 – Aug 6 |
| Spinach | Sow outdoors (spring) | Apr 10 – May 24 |
| Spinach | Sow outdoors (fall) | Jul 7 – Aug 11 |
| Radishes | Sow outdoors (spring) | Apr 17 – Jun 7 |
| Radishes | Sow outdoors (fall) | Jun 20 – Aug 21 |
| Kale | Sow outdoors (spring) | May 4 – May 24 |
| Kale | Sow outdoors (fall) | Jun 13 – Jul 21 |
| Carrots | Sow outdoors (spring) | May 18 – Jul 3 |
| Carrots | Sow outdoors (fall) | May 21 – Jul 6 |
| Garlic | Plant outdoors (fall) | Sep 20 – Oct 21 |
Where these dates come from
ZIP code 83423 is matched to the NOAA station Dubois Exp Stn, ID, 11.9 km away, at 5,450 ft elevation (316 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Dubois Exp Stn, ID (used) | 5,450 ft | May 18 | Sep 30 |
| Small 6N, ID | 5,740 ft | Jun 5 | Sep 20 |
| Hamer 4 Nw, ID | 4,790 ft | Jun 3 | Sep 11 |
| Monteview, ID | 4,815 ft | Jun 12 | Sep 7 |
Frost dates near Dubois
- Spencer, ID 83446 · last May 18, first Sep 30
- Monteview, ID 83435 · last Jun 12, first Sep 7
- Hamer, ID 83425 · last Jun 3, first Sep 11
- Terreton, ID 83450 · last Jun 3, first Sep 11
- Parker, ID 83438 · last May 17, first Sep 22
- Lima, MT 59739 · last Jun 11, first Sep 10
- Roberts, ID 83444 · last May 23, first Sep 20
- Saint Anthony, ID 83445 · last May 17, first Sep 22
Frequently asked questions
- When is the last frost in Dubois, ID?
- For ZIP code 83423, the average last spring frost (32°F) is May 18, based on NOAA 1991-2020 climate normals for the Dubois Exp Stn, ID weather station. There is a 1-in-10 chance of a frost after June 9.
- When is the first frost in Dubois, ID?
- The average first fall frost (32°F) is September 30. 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 83423?
- 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.