Frost dates for 59418Buffalo, MT
The average last spring frost in Buffalo is May 28 and the average first fall frost is September 20, giving a typical growing season of about 112 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 28
- Average first fall frost
- Sep 20
- Growing season
- 112 days
Safer after Jun 19 (1-in-10 risk)
Possible by Sep 4 (1-in-10 risk)
Last frost typically in 213 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) | — | — | 83 days | 100% |
| Frost / freeze (32°F) | May 13 · May 28 · Jun 19 | Sep 4 · Sep 20 · Oct 2 | 112 days | 100% |
| Hard freeze (28°F) | May 1 · May 12 · May 29 | Sep 18 · Sep 30 · Oct 15 | 141 days | 100% |
Planting calendar for Buffalo
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 27 – Jul 3 |
| Tomatoes | Transplant outdoors | Jun 13 – May 31 |
| Peppers | Start seeds indoors | Apr 27 – May 28 |
| Peppers | Transplant outdoors | Jun 27 – Jul 28 |
| Eggplant | Start seeds indoors | May 14 – Jun 12 |
| Eggplant | Transplant outdoors | Jun 27 – Jul 28 |
| Cucumbers | Sow outdoors | Jun 27 – Jun 10 |
| Summer squash | Sow outdoors | Jun 13 – Jul 28 |
| Winter squash & pumpkins | Sow outdoors | Jun 27 – Jul 28 |
| Snap beans | Sow outdoors | Jun 13 – Jul 3 |
| Sweet corn | Sow outdoors | Jun 13 – May 31 |
| Watermelon & cantaloupe | Sow outdoors | Jun 27 – Jul 28 |
| Okra | Sow outdoors | Jun 20 – Jul 13 |
| Peas | Sow outdoors (spring) | Apr 27 – Jun 12 |
| Potatoes | Plant outdoors (spring) | Apr 27 – Jun 27 |
| Onions | Start seeds indoors (spring) | Mar 16 – Apr 12 |
| Onions | Transplant outdoors (spring) | May 14 – Jun 12 |
| Broccoli | Start seeds indoors (spring) | Apr 9 – May 13 |
| Broccoli | Transplant outdoors (spring) | May 14 – Jun 12 |
| Broccoli | Start seeds indoors (fall) | May 21 – May 31 |
| Broccoli | Transplant outdoors (fall) | Jun 20 – Jul 1 |
| Cabbage | Start seeds indoors (spring) | Mar 30 – Apr 27 |
| Cabbage | Transplant outdoors (spring) | Apr 27 – May 28 |
| Cabbage | Start seeds indoors (fall) | May 11 – Jun 10 |
| Cabbage | Transplant outdoors (fall) | Jun 10 – Jul 11 |
| Leaf lettuce | Sow outdoors (spring) | Apr 27 – Jul 13 |
| Leaf lettuce | Sow outdoors (fall) | Jun 10 – Jul 27 |
| Spinach | Sow outdoors (spring) | Apr 20 – Jun 3 |
| Spinach | Sow outdoors (fall) | Jun 27 – Aug 1 |
| Radishes | Sow outdoors (spring) | Apr 27 – Jun 17 |
| Radishes | Sow outdoors (fall) | Jun 10 – Aug 11 |
| Kale | Sow outdoors (spring) | May 14 – Jun 3 |
| Kale | Sow outdoors (fall) | Jun 3 – Jul 11 |
| Carrots | Sow outdoors (spring) | May 28 – Jul 13 |
| Carrots | Sow outdoors (fall) | May 11 – Jun 26 |
| Garlic | Plant outdoors (fall) | Sep 10 – Oct 11 |
Where these dates come from
ZIP code 59418 is matched to the NOAA station Moccasin Exp Stn, MT, 27.9 km away, at 4,300 ft elevation (21 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Moccasin Exp Stn, MT (used) | 4,300 ft | May 28 | Sep 20 |
| Judith Gap, MT | 4,630 ft | Jun 1 | Sep 15 |
| Harlowton 11Nw, MT | 4,954 ft | May 30 | Sep 20 |
| Lewistown 11 Sse, MT | 4,965 ft | May 31 | Sep 14 |
Frost dates near Buffalo
- Hobson, MT 59452 · last May 28, first Sep 20
- Moore, MT 59464 · last May 23, first Sep 21
- Judith Gap, MT 59453 · last Jun 1, first Sep 15
- Moccasin, MT 59462 · last May 28, first Sep 20
- Lewistown, MT 59457 · last May 23, first Sep 21
- Harlowton, MT 59036 · last May 23, first Sep 16
- Stanford, MT 59479 · last May 28, first Sep 20
- Two Dot, MT 59085 · last May 23, first Sep 16
Frequently asked questions
- When is the last frost in Buffalo, MT?
- For ZIP code 59418, the average last spring frost (32°F) is May 28, based on NOAA 1991-2020 climate normals for the Moccasin Exp Stn, MT weather station. There is a 1-in-10 chance of a frost after June 19.
- When is the first frost in Buffalo, MT?
- The average first fall frost (32°F) is September 20. There is a 1-in-10 chance of frost by September 4, so tender plants are at risk from that point on.
- How long is the growing season in 59418?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 112 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.