Frost dates for 59921Lake Mc Donald, MT
The average last spring frost in Lake Mc Donald is May 9 and the average first fall frost is October 1, giving a typical growing season of about 141 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 9
- Average first fall frost
- Oct 1
- Growing season
- 141 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 13 (1-in-10 risk)
Last frost typically in 194 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 28 · Jun 19 | Aug 31 · Sep 19 · Oct 2 | 110 days | 100% |
| Frost / freeze (32°F) | Apr 25 · May 9 · May 30 | Sep 13 · Oct 1 · Oct 17 | 141 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 27 · May 14 | Sep 30 · Oct 14 · Oct 31 | 170 days | 100% |
Planting calendar for Lake Mc Donald
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 11 |
| 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 21 |
| Summer squash | Sow outdoors | May 25 – Jul 9 |
| Winter squash & pumpkins | Sow outdoors | Jun 8 – Jul 9 |
| Snap beans | Sow outdoors | May 25 – Jul 14 |
| Sweet corn | Sow outdoors | May 25 – Jun 11 |
| 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 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 11 – Apr 8 |
| Cabbage | Transplant outdoors (spring) | Apr 8 – May 9 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 8 – Jun 24 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Apr 1 – May 15 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 8 – May 29 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | Apr 25 – May 15 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 9 – Jun 24 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 59921 is matched to the NOAA station Hungry Horse Dam, MT, 7.2 km away, at 3,160 ft elevation (393 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hungry Horse Dam, MT (used) | 3,160 ft | May 9 | Oct 1 |
| Creston, MT | 2,935 ft | May 12 | Sep 25 |
| W Glacier, MT | 3,148 ft | May 18 | Sep 20 |
| Kalispell Glacier Ap, MT | 2,957 ft | May 31 | Sep 10 |
Frost dates near Lake Mc Donald
- Martin City, MT 59926 · last May 9, first Oct 1
- Hungry Horse, MT 59919 · last May 9, first Oct 1
- Coram, MT 59913 · last May 18, first Sep 20
- Columbia Falls, MT 59912 · last May 31, first Sep 10
- West Glacier, MT 59936 · last May 18, first Sep 20
- Kalispell, MT 59904 · last May 31, first Sep 10
- Essex, MT 59916 · last May 9, first Oct 1
- Bigfork, MT 59911 · last May 12, first Sep 25
Frequently asked questions
- When is the last frost in Lake Mc Donald, MT?
- For ZIP code 59921, the average last spring frost (32°F) is May 9, based on NOAA 1991-2020 climate normals for the Hungry Horse Dam, MT weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Lake Mc Donald, MT?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 13, so tender plants are at risk from that point on.
- How long is the growing season in 59921?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 141 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.