Frost dates for 59311Alzada, MT
The average last spring frost in Alzada is June 2 and the average first fall frost is September 6, giving a typical growing season of about 95 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 2
- Average first fall frost
- Sep 6
- Growing season
- 95 days
Safer after Jun 21 (1-in-10 risk)
Possible by Aug 23 (1-in-10 risk)
Last frost typically in 218 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) | — | — | 69 days | 100% |
| Frost / freeze (32°F) | May 18 · Jun 2 · Jun 21 | Aug 23 · Sep 6 · Sep 20 | 95 days | 100% |
| Hard freeze (28°F) | May 9 · May 21 · Jun 5 | Sep 1 · Sep 16 · Sep 29 | 116 days | 100% |
Planting calendar for Alzada
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 | May 2 – Jul 8 |
| Tomatoes | Transplant outdoors | Jun 18 – May 17 |
| Peppers | Start seeds indoors | May 2 – Jun 2 |
| Peppers | Transplant outdoors | Jul 2 – Aug 2 |
| Eggplant | Start seeds indoors | May 19 – Jun 17 |
| Eggplant | Transplant outdoors | Jul 2 – Aug 2 |
| Cucumbers | Sow outdoors | Jul 2 – May 27 |
| Summer squash | Sow outdoors | Jun 18 – Aug 2 |
| Winter squash & pumpkins | Sow outdoors | Jul 2 – Aug 2 |
| Snap beans | Sow outdoors | Jun 18 – Jun 19 |
| Sweet corn | Sow outdoors | Jun 18 – May 17 |
| Watermelon & cantaloupe | Sow outdoors | Jul 2 – Aug 2 |
| Okra | Sow outdoors | Jun 25 – Jul 18 |
| Peas | Sow outdoors (spring) | May 2 – Jun 17 |
| Potatoes | Plant outdoors (spring) | May 2 – Jul 2 |
| Onions | Start seeds indoors (spring) | Mar 21 – Apr 17 |
| Onions | Transplant outdoors (spring) | May 19 – Jun 17 |
| Broccoli | Start seeds indoors (spring) | Apr 14 – May 18 |
| Broccoli | Transplant outdoors (spring) | May 19 – Jun 17 |
| Broccoli | Start seeds indoors (fall) | May 7 – May 17 |
| Broccoli | Transplant outdoors (fall) | Jun 6 – Jun 17 |
| Cabbage | Start seeds indoors (spring) | Apr 4 – May 2 |
| Cabbage | Transplant outdoors (spring) | May 2 – Jun 2 |
| Cabbage | Start seeds indoors (fall) | Apr 27 – May 27 |
| Cabbage | Transplant outdoors (fall) | May 27 – Jun 27 |
| Leaf lettuce | Sow outdoors (spring) | May 2 – Jul 18 |
| Leaf lettuce | Sow outdoors (fall) | May 27 – Jul 13 |
| Spinach | Sow outdoors (spring) | Apr 25 – Jun 8 |
| Spinach | Sow outdoors (fall) | Jun 13 – Jul 18 |
| Radishes | Sow outdoors (spring) | May 2 – Jun 22 |
| Radishes | Sow outdoors (fall) | May 27 – Jul 28 |
| Kale | Sow outdoors (spring) | May 19 – Jun 8 |
| Kale | Sow outdoors (fall) | May 20 – Jun 27 |
| Carrots | Sow outdoors (spring) | Jun 2 – Jul 18 |
| Carrots | Sow outdoors (fall) | Apr 27 – Jun 12 |
| Garlic | Plant outdoors (fall) | Aug 27 – Sep 27 |
Where these dates come from
ZIP code 59311 is matched to the NOAA station Albion 1 N, MT, 5.9 km away, at 3,312 ft elevation (80 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Albion 1 N, MT (used) | 3,312 ft | Jun 2 | Sep 6 |
| Belle Fourche 22 Nnw, SD | 3,200 ft | May 15 | Sep 24 |
| Colony, WY | 3,480 ft | May 7 | Oct 3 |
| Ridgeway 1 S, MT | 3,316 ft | May 17 | Sep 22 |
Frost dates near Alzada
- Capitol, MT 59319 · last May 17, first Sep 24
- Aladdin, WY 82710 · last May 7, first Oct 3
- Hammond, MT 59332 · last May 17, first Sep 22
- Alva, WY 82711 · last May 17, first Sep 23
- Hulett, WY 82720 · last May 17, first Sep 23
- Camp Crook, SD 57724 · last May 17, first Sep 24
- Redig, SD 57776 · last May 15, first Sep 24
- Boyes, MT 59316 · last May 16, first Sep 28
Frequently asked questions
- When is the last frost in Alzada, MT?
- For ZIP code 59311, the average last spring frost (32°F) is June 2, based on NOAA 1991-2020 climate normals for the Albion 1 N, MT weather station. There is a 1-in-10 chance of a frost after June 21.
- When is the first frost in Alzada, MT?
- The average first fall frost (32°F) is September 6. There is a 1-in-10 chance of frost by August 23, so tender plants are at risk from that point on.
- How long is the growing season in 59311?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 95 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.