Frost dates for 59273Vandalia, MT
The average last spring frost in Vandalia is May 3 and the average first fall frost is October 1, giving a typical growing season of about 151 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 1
- Growing season
- 151 days
Safer after May 15 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 188 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 2 · May 14 · May 26 | Sep 11 · Sep 23 · Oct 4 | 131 days | 100% |
| Frost / freeze (32°F) | Apr 19 · May 3 · May 15 | Sep 19 · Oct 1 · Oct 15 | 151 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 23 · May 6 | Sep 25 · Oct 11 · Oct 25 | 170 days | 100% |
Planting calendar for Vandalia
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 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 11 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jun 21 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 14 |
| Sweet corn | Sow outdoors | May 19 – Jun 11 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 59273 is matched to the NOAA station Glasgow #2, MT, 27 km away, at 2,090 ft elevation (36 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Glasgow #2, MT (used) | 2,090 ft | May 3 | Oct 1 |
| Hinsdale 4 Sw, MT | 2,805 ft | May 15 | Sep 26 |
| Glasgow Intl Ap, MT | 2,285 ft | May 6 | Sep 30 |
| St Marie, MT | 2,756 ft | May 13 | Sep 27 |
Frost dates near Vandalia
- Hinsdale, MT 59241 · last May 15, first Sep 23
- Saint Marie, MT 59231 · last May 13, first Sep 27
- Glasgow, MT 59230 · last May 6, first Sep 30
- Nashua, MT 59248 · last May 12, first Sep 24
- Saco, MT 59261 · last May 15, first Sep 23
- Fort Peck, MT 59223 · last May 8, first Oct 1
- Larslan, MT 59244 · last Jun 5, first Sep 2
- Frazer, MT 59225 · last May 13, first Sep 27
Frequently asked questions
- When is the last frost in Vandalia, MT?
- For ZIP code 59273, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Glasgow #2, MT weather station. There is a 1-in-10 chance of a frost after May 15.
- When is the first frost in Vandalia, MT?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 59273?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 151 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.