Frost dates for 59711Anaconda, MT
The average last spring frost in Anaconda is June 1 and the average first fall frost is September 14, giving a typical growing season of about 105 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 1
- Average first fall frost
- Sep 14
- Growing season
- 105 days
Safer after Jun 25 (1-in-10 risk)
Possible by Aug 31 (1-in-10 risk)
Last frost typically in 217 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) | — | — | 71 days | 100% |
| Frost / freeze (32°F) | May 14 · Jun 1 · Jun 25 | Aug 31 · Sep 14 · Oct 1 | 105 days | 100% |
| Hard freeze (28°F) | Apr 29 · May 13 · May 30 | Sep 12 · Sep 28 · Oct 12 | 138 days | 100% |
Planting calendar for Anaconda
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 1 – Jul 7 |
| Tomatoes | Transplant outdoors | Jun 17 – May 25 |
| Peppers | Start seeds indoors | May 1 – Jun 1 |
| Peppers | Transplant outdoors | Jul 1 – Aug 1 |
| Eggplant | Start seeds indoors | May 18 – Jun 16 |
| Eggplant | Transplant outdoors | Jul 1 – Aug 1 |
| Cucumbers | Sow outdoors | Jul 1 – Jun 4 |
| Summer squash | Sow outdoors | Jun 17 – Aug 1 |
| Winter squash & pumpkins | Sow outdoors | Jul 1 – Aug 1 |
| Snap beans | Sow outdoors | Jun 17 – Jun 27 |
| Sweet corn | Sow outdoors | Jun 17 – May 25 |
| Watermelon & cantaloupe | Sow outdoors | Jul 1 – Aug 1 |
| Okra | Sow outdoors | Jun 24 – Jul 17 |
| Peas | Sow outdoors (spring) | May 1 – Jun 16 |
| Potatoes | Plant outdoors (spring) | May 1 – Jul 1 |
| Onions | Start seeds indoors (spring) | Mar 20 – Apr 16 |
| Onions | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (spring) | Apr 13 – May 17 |
| Broccoli | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (fall) | May 15 – May 25 |
| Broccoli | Transplant outdoors (fall) | Jun 14 – Jun 25 |
| Cabbage | Start seeds indoors (spring) | Apr 3 – May 1 |
| Cabbage | Transplant outdoors (spring) | May 1 – Jun 1 |
| Cabbage | Start seeds indoors (fall) | May 5 – Jun 4 |
| Cabbage | Transplant outdoors (fall) | Jun 4 – Jul 5 |
| Leaf lettuce | Sow outdoors (spring) | May 1 – Jul 17 |
| Leaf lettuce | Sow outdoors (fall) | Jun 4 – Jul 21 |
| Spinach | Sow outdoors (spring) | Apr 24 – Jun 7 |
| Spinach | Sow outdoors (fall) | Jun 21 – Jul 26 |
| Radishes | Sow outdoors (spring) | May 1 – Jun 21 |
| Radishes | Sow outdoors (fall) | Jun 4 – Aug 5 |
| Kale | Sow outdoors (spring) | May 18 – Jun 7 |
| Kale | Sow outdoors (fall) | May 28 – Jul 5 |
| Carrots | Sow outdoors (spring) | Jun 1 – Jul 17 |
| Carrots | Sow outdoors (fall) | May 5 – Jun 20 |
| Garlic | Plant outdoors (fall) | Sep 4 – Oct 5 |
Where these dates come from
ZIP code 59711 is matched to the NOAA station Anaconda, MT, 3.1 km away, at 5,230 ft elevation (180 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Anaconda, MT (used) | 5,230 ft | Jun 1 | Sep 14 |
| Deer Lodge 3 W, MT | 4,850 ft | — | — |
| Phillipsburg Rs, MT | 5,270 ft | — | — |
| Wise Rvr 3 Wnw, MT | 5,730 ft | — | — |
Frost dates near Anaconda
- Warm Springs, MT 59756 · last —, first —
- Butte, MT 59750 · last Jun 13, first Sep 5
- Ramsay, MT 59748 · last Jun 13, first Sep 5
- Philipsburg, MT 59858 · last —, first —
- Deer Lodge, MT 59722 · last —, first —
- Divide, MT 59727 · last —, first —
- Wise River, MT 59762 · last —, first —
- Gold Creek, MT 59733 · last —, first —
Frequently asked questions
- When is the last frost in Anaconda, MT?
- For ZIP code 59711, the average last spring frost (32°F) is June 1, based on NOAA 1991-2020 climate normals for the Anaconda, MT weather station. There is a 1-in-10 chance of a frost after June 25.
- When is the first frost in Anaconda, MT?
- The average first fall frost (32°F) is September 14. There is a 1-in-10 chance of frost by August 31, so tender plants are at risk from that point on.
- How long is the growing season in 59711?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 105 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.