Last spring frost
Apr 30
Frost Dates for Pony, MT
First fall frost
Oct 10
Growing season
162 days
Hardiness zone
5a
In an average year around Pony, MT, the last spring frost (32°F) is about Apr 30 and the first fall frost is about Oct 10, giving roughly a 162-day growing season. To be safe most years, wait until Apr 15 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 2 | May 15 | Apr 30 |
| Freeze (32°F) | May 14 | Apr 30 | Apr 15 |
| Hard (28°F) | May 5 | Apr 17 | Apr 1 |
| Severe (24°F) | Apr 22 | Apr 1 | Mar 10 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 2 | May 26 | May 22 | May 18 | May 15 | May 12 | May 8 | May 4 | Apr 30 |
| 32°F | May 14 | May 9 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 25 | Apr 20 | Apr 15 |
| 28°F | May 5 | Apr 30 | Apr 24 | Apr 21 | Apr 17 | Apr 13 | Apr 9 | Apr 5 | Apr 1 |
| 24°F | Apr 22 | Apr 14 | Apr 8 | Apr 4 | Apr 1 | Mar 29 | Mar 24 | Mar 18 | Mar 10 |
| 20°F | Apr 8 | Apr 1 | Mar 27 | Mar 23 | Mar 18 | Mar 14 | Mar 9 | Mar 5 | Feb 27 |
| 16°F | Mar 29 | Mar 21 | Mar 16 | Mar 11 | Mar 7 | Mar 3 | Feb 28 | Feb 21 | Feb 11 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Sep 17 | Sep 30 | Oct 13 |
| Freeze (32°F) | Sep 27 | Oct 10 | Oct 27 |
| Hard (28°F) | Oct 4 | Oct 22 | Nov 7 |
| Severe (24°F) | Oct 16 | Nov 2 | Nov 20 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 13 |
| 32°F | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 18 | Oct 22 | Oct 27 |
| 28°F | Oct 4 | Oct 10 | Oct 15 | Oct 18 | Oct 22 | Oct 25 | Oct 30 | Nov 2 | Nov 7 |
| 24°F | Oct 16 | Oct 21 | Oct 26 | Oct 30 | Nov 2 | Nov 5 | Nov 9 | Nov 14 | Nov 20 |
| 20°F | Oct 25 | Oct 31 | Nov 4 | Nov 8 | Nov 11 | Nov 15 | Nov 19 | Nov 22 | Nov 28 |
| 16°F | Oct 31 | Nov 6 | Nov 10 | Nov 14 | Nov 19 | Nov 22 | Nov 26 | Dec 1 | Dec 8 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Norris Madison Pwr House, Mt, about 15.3 miles away@if(!empty($station['elevation_ft'])), at 4,745 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Pony, MT?
On average, the last spring frost (32°F) around Pony, MT is about Apr 30. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 15.
When is the first frost in the fall?
The first fall frost around Pony, MT typically arrives about Oct 10. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 30 on average, or Apr 15 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 162 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 59735 Planting calendar → Montana frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026