Frost dates for 59033Greycliff, MT
The average last spring frost in Greycliff is May 14 and the average first fall frost is September 26, giving a typical growing season of about 133 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 14
- Average first fall frost
- Sep 26
- Growing season
- 133 days
Safer after May 27 (1-in-10 risk)
Possible by Sep 10 (1-in-10 risk)
Last frost typically in 192 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 16 · May 28 · Jun 12 | Aug 28 · Sep 13 · Sep 28 | 106 days | 100% |
| Frost / freeze (32°F) | May 2 · May 14 · May 27 | Sep 10 · Sep 26 · Oct 8 | 133 days | 100% |
| Hard freeze (28°F) | Apr 18 · May 2 · May 16 | Sep 22 · Oct 5 · Oct 21 | 156 days | 100% |
Planting calendar for Greycliff
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 13 – Jun 19 |
| Tomatoes | Transplant outdoors | May 30 – Jun 6 |
| Peppers | Start seeds indoors | Apr 13 – May 14 |
| Peppers | Transplant outdoors | Jun 13 – Jul 14 |
| Eggplant | Start seeds indoors | Apr 30 – May 29 |
| Eggplant | Transplant outdoors | Jun 13 – Jul 14 |
| Cucumbers | Sow outdoors | Jun 13 – Jun 16 |
| Summer squash | Sow outdoors | May 30 – Jul 14 |
| Winter squash & pumpkins | Sow outdoors | Jun 13 – Jul 14 |
| Snap beans | Sow outdoors | May 30 – Jul 9 |
| Sweet corn | Sow outdoors | May 30 – Jun 6 |
| Watermelon & cantaloupe | Sow outdoors | Jun 13 – Jul 14 |
| Okra | Sow outdoors | Jun 6 – Jun 29 |
| Peas | Sow outdoors (spring) | Apr 13 – May 29 |
| Potatoes | Plant outdoors (spring) | Apr 13 – Jun 13 |
| Onions | Start seeds indoors (spring) | Mar 2 – Mar 29 |
| Onions | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (spring) | Mar 26 – Apr 29 |
| Broccoli | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (fall) | May 27 – Jun 6 |
| Broccoli | Transplant outdoors (fall) | Jun 26 – Jul 7 |
| Cabbage | Start seeds indoors (spring) | Mar 16 – Apr 13 |
| Cabbage | Transplant outdoors (spring) | Apr 13 – May 14 |
| Cabbage | Start seeds indoors (fall) | May 17 – Jun 16 |
| Cabbage | Transplant outdoors (fall) | Jun 16 – Jul 17 |
| Leaf lettuce | Sow outdoors (spring) | Apr 13 – Jun 29 |
| Leaf lettuce | Sow outdoors (fall) | Jun 16 – Aug 2 |
| Spinach | Sow outdoors (spring) | Apr 6 – May 20 |
| Spinach | Sow outdoors (fall) | Jul 3 – Aug 7 |
| Radishes | Sow outdoors (spring) | Apr 13 – Jun 3 |
| Radishes | Sow outdoors (fall) | Jun 16 – Aug 17 |
| Kale | Sow outdoors (spring) | Apr 30 – May 20 |
| Kale | Sow outdoors (fall) | Jun 9 – Jul 17 |
| Carrots | Sow outdoors (spring) | May 14 – Jun 29 |
| Carrots | Sow outdoors (fall) | May 17 – Jul 2 |
| Garlic | Plant outdoors (fall) | Sep 16 – Oct 17 |
Where these dates come from
ZIP code 59033 is matched to the NOAA station Big Timber, MT, 15 km away, at 4,100 ft elevation (166 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Big Timber, MT (used) | 4,100 ft | May 14 | Sep 26 |
| Nye #2, MT | 4,840 ft | Jun 1 | Sep 11 |
| Gibson 2 Ne, MT | 4,444 ft | May 27 | Sep 18 |
| Columbus, MT | 3,602 ft | May 27 | Sep 14 |
Frost dates near Greycliff
- Big Timber, MT 59011 · last May 14, first Sep 26
- Reed Point, MT 59069 · last May 24, first Sep 21
- Mc Leod, MT 59052 · last Jun 5, first Sep 14
- Springdale, MT 59082 · last May 14, first Sep 26
- Nye, MT 59061 · last Jun 1, first Sep 11
- Absarokee, MT 59001 · last Jun 1, first Sep 11
- Melville, MT 59055 · last Jun 9, first Sep 7
- Fishtail, MT 59028 · last Jun 3, first Sep 19
Frequently asked questions
- When is the last frost in Greycliff, MT?
- For ZIP code 59033, the average last spring frost (32°F) is May 14, based on NOAA 1991-2020 climate normals for the Big Timber, MT weather station. There is a 1-in-10 chance of a frost after May 27.
- When is the first frost in Greycliff, MT?
- The average first fall frost (32°F) is September 26. There is a 1-in-10 chance of frost by September 10, so tender plants are at risk from that point on.
- How long is the growing season in 59033?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 133 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.