Frost dates for 59075Saint Xavier, MT
The average last spring frost in Saint Xavier is May 7 and the average first fall frost is October 5, giving a typical growing season of about 151 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 7
- Average first fall frost
- Oct 5
- Growing season
- 151 days
Safer after May 24 (1-in-10 risk)
Possible by Sep 20 (1-in-10 risk)
Last frost typically in 185 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 5 · May 20 · Jun 4 | Sep 9 · Sep 26 · Oct 9 | 127 days | 100% |
| Frost / freeze (32°F) | Apr 20 · May 7 · May 24 | Sep 20 · Oct 5 · Oct 22 | 151 days | 100% |
| Hard freeze (28°F) | Apr 5 · Apr 24 · May 13 | Sep 30 · Oct 14 · Nov 1 | 175 days | 100% |
Planting calendar for Saint Xavier
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 6 – Jun 12 |
| Tomatoes | Transplant outdoors | May 23 – Jun 15 |
| Peppers | Start seeds indoors | Apr 6 – May 7 |
| Peppers | Transplant outdoors | Jun 6 – Jul 7 |
| Eggplant | Start seeds indoors | Apr 23 – May 22 |
| Eggplant | Transplant outdoors | Jun 6 – Jul 7 |
| Cucumbers | Sow outdoors | Jun 6 – Jun 25 |
| Summer squash | Sow outdoors | May 23 – Jul 7 |
| Winter squash & pumpkins | Sow outdoors | Jun 6 – Jul 7 |
| Snap beans | Sow outdoors | May 23 – Jul 18 |
| Sweet corn | Sow outdoors | May 23 – Jun 15 |
| Watermelon & cantaloupe | Sow outdoors | Jun 6 – Jul 7 |
| Okra | Sow outdoors | May 30 – Jun 22 |
| Peas | Sow outdoors (spring) | Apr 6 – May 22 |
| Potatoes | Plant outdoors (spring) | Apr 6 – Jun 6 |
| Onions | Start seeds indoors (spring) | Feb 23 – Mar 22 |
| Onions | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (spring) | Mar 19 – Apr 22 |
| Broccoli | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (fall) | Jun 5 – Jun 15 |
| Broccoli | Transplant outdoors (fall) | Jul 5 – Jul 16 |
| Cabbage | Start seeds indoors (spring) | Mar 9 – Apr 6 |
| Cabbage | Transplant outdoors (spring) | Apr 6 – May 7 |
| Cabbage | Start seeds indoors (fall) | May 26 – Jun 25 |
| Cabbage | Transplant outdoors (fall) | Jun 25 – Jul 26 |
| Leaf lettuce | Sow outdoors (spring) | Apr 6 – Jun 22 |
| Leaf lettuce | Sow outdoors (fall) | Jun 25 – Aug 11 |
| Spinach | Sow outdoors (spring) | Mar 30 – May 13 |
| Spinach | Sow outdoors (fall) | Jul 12 – Aug 16 |
| Radishes | Sow outdoors (spring) | Apr 6 – May 27 |
| Radishes | Sow outdoors (fall) | Jun 25 – Aug 26 |
| Kale | Sow outdoors (spring) | Apr 23 – May 13 |
| Kale | Sow outdoors (fall) | Jun 18 – Jul 26 |
| Carrots | Sow outdoors (spring) | May 7 – Jun 22 |
| Carrots | Sow outdoors (fall) | May 26 – Jul 11 |
| Garlic | Plant outdoors (fall) | Sep 25 – Oct 26 |
Where these dates come from
ZIP code 59075 is matched to the NOAA station Yellowtail Dam, MT, 10.3 km away, at 3,305 ft elevation (340 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Yellowtail Dam, MT (used) | 3,305 ft | May 7 | Oct 5 |
| Hardin, MT | 2,880 ft | May 13 | Sep 29 |
| Wyola 1 Sw, MT | 3,730 ft | May 21 | Sep 17 |
| Billings Wtp, MT | 3,097 ft | May 10 | Oct 1 |
Frost dates near Saint Xavier
- Fort Smith, MT 59035 · last May 7, first Oct 5
- Garryowen, MT 59031 · last May 7, first Oct 5
- Crow Agency, MT 59022 · last May 13, first Sep 29
- Lodge Grass, MT 59050 · last May 23, first Sep 15
- Hardin, MT 59034 · last May 13, first Sep 29
- Wyola, MT 59089 · last May 21, first Sep 17
- Pryor, MT 59066 · last May 29, first Sep 15
- Billings, MT 59107 · last May 10, first Oct 1
Frequently asked questions
- When is the last frost in Saint Xavier, MT?
- For ZIP code 59075, the average last spring frost (32°F) is May 7, based on NOAA 1991-2020 climate normals for the Yellowtail Dam, MT weather station. There is a 1-in-10 chance of a frost after May 24.
- When is the first frost in Saint Xavier, MT?
- The average first fall frost (32°F) is October 5. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 59075?
- 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.