Frost dates for 59062Otter, MT
The average last spring frost in Otter is May 25 and the average first fall frost is September 19, giving a typical growing season of about 115 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 25
- Average first fall frost
- Sep 19
- Growing season
- 115 days
Safer after Jun 7 (1-in-10 risk)
Possible by Sep 1 (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 23 · Jun 7 · Jun 27 | Aug 18 · Sep 6 · Sep 20 | 89 days | 100% |
| Frost / freeze (32°F) | May 12 · May 25 · Jun 7 | Sep 1 · Sep 19 · Oct 1 | 115 days | 100% |
| Hard freeze (28°F) | May 2 · May 14 · May 27 | Sep 14 · Sep 29 · Oct 12 | 136 days | 100% |
Planting calendar for Otter
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 24 – Jun 30 |
| Tomatoes | Transplant outdoors | Jun 10 – May 30 |
| Peppers | Start seeds indoors | Apr 24 – May 25 |
| Peppers | Transplant outdoors | Jun 24 – Jul 25 |
| Eggplant | Start seeds indoors | May 11 – Jun 9 |
| Eggplant | Transplant outdoors | Jun 24 – Jul 25 |
| Cucumbers | Sow outdoors | Jun 24 – Jun 9 |
| Summer squash | Sow outdoors | Jun 10 – Jul 25 |
| Winter squash & pumpkins | Sow outdoors | Jun 24 – Jul 25 |
| Snap beans | Sow outdoors | Jun 10 – Jul 2 |
| Sweet corn | Sow outdoors | Jun 10 – May 30 |
| Watermelon & cantaloupe | Sow outdoors | Jun 24 – Jul 25 |
| Okra | Sow outdoors | Jun 17 – Jul 10 |
| Peas | Sow outdoors (spring) | Apr 24 – Jun 9 |
| Potatoes | Plant outdoors (spring) | Apr 24 – Jun 24 |
| Onions | Start seeds indoors (spring) | Mar 13 – Apr 9 |
| Onions | Transplant outdoors (spring) | May 11 – Jun 9 |
| Broccoli | Start seeds indoors (spring) | Apr 6 – May 10 |
| Broccoli | Transplant outdoors (spring) | May 11 – Jun 9 |
| Broccoli | Start seeds indoors (fall) | May 20 – May 30 |
| Broccoli | Transplant outdoors (fall) | Jun 19 – Jun 30 |
| Cabbage | Start seeds indoors (spring) | Mar 27 – Apr 24 |
| Cabbage | Transplant outdoors (spring) | Apr 24 – May 25 |
| Cabbage | Start seeds indoors (fall) | May 10 – Jun 9 |
| Cabbage | Transplant outdoors (fall) | Jun 9 – Jul 10 |
| Leaf lettuce | Sow outdoors (spring) | Apr 24 – Jul 10 |
| Leaf lettuce | Sow outdoors (fall) | Jun 9 – Jul 26 |
| Spinach | Sow outdoors (spring) | Apr 17 – May 31 |
| Spinach | Sow outdoors (fall) | Jun 26 – Jul 31 |
| Radishes | Sow outdoors (spring) | Apr 24 – Jun 14 |
| Radishes | Sow outdoors (fall) | Jun 9 – Aug 10 |
| Kale | Sow outdoors (spring) | May 11 – May 31 |
| Kale | Sow outdoors (fall) | Jun 2 – Jul 10 |
| Carrots | Sow outdoors (spring) | May 25 – Jul 10 |
| Carrots | Sow outdoors (fall) | May 10 – Jun 25 |
| Garlic | Plant outdoors (fall) | Sep 9 – Oct 10 |
Where these dates come from
ZIP code 59062 is matched to the NOAA station Sonnette 7 Sw, MT, 31.9 km away, at 3,914 ft elevation (23 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Sonnette 7 Sw, MT (used) | 3,914 ft | May 25 | Sep 19 |
| Leiter 9N, WY | 4,160 ft | May 14 | Sep 30 |
| Moorhead 9 Ne, MT | 3,220 ft | May 17 | Sep 22 |
| Biddle 8 Sw, MT | 3,631 ft | May 14 | Sep 28 |
Frost dates near Otter
- Birney, MT 59012 · last May 23, first Sep 15
- Leiter, WY 82837 · last May 24, first Sep 16
- Arvada, WY 82831 · last May 21, first Sep 23
- Recluse, WY 82725 · last May 21, first Sep 23
- Clearmont, WY 82835 · last May 24, first Sep 16
- Ashland, MT 59003 · last May 18, first Sep 22
- Wyarno, WY 82845 · last May 21, first Sep 23
- Decker, MT 59025 · last May 21, first Sep 23
Frequently asked questions
- When is the last frost in Otter, MT?
- For ZIP code 59062, the average last spring frost (32°F) is May 25, based on NOAA 1991-2020 climate normals for the Sonnette 7 Sw, MT weather station. There is a 1-in-10 chance of a frost after June 7.
- When is the first frost in Otter, MT?
- The average first fall frost (32°F) is September 19. There is a 1-in-10 chance of frost by September 1, so tender plants are at risk from that point on.
- How long is the growing season in 59062?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 115 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.