USDA Hardiness Zone 4a
Frost Dates for 59427 — Cut Bank, Montana
NOAA 1991–2020 normals from Cut Bank Municipal Airport, MT (3,838 ft), 7 miles southeast.
Updated
In Cut Bank, the last spring frost (32°F) is around May 24 in half of years and has passed by June 5 in nine years out of ten. The first fall frost comes around September 15, as early as September 1 one year in ten, leaving a typical freeze-free season of 113 days (NOAA, Cut Bank Municipal Airport, MT).
- Last spring frost
- May 24
- First fall frost
- September 15
- Growing season
- 113 days
- Hardiness zone
- 4a
50% probability
50% probability
freeze-free, 50%
-30 to -25°F (-34.4 to -31.7°C) coldest night
- First snow
- October 9
- Last snow
- April 28
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
18 of 18 observed
NOAA normal
Frost risk by date in Cut Bank
Half of springs at Cut Bank Municipal Airport, MT see their last 32°F night by May 24; only one in ten is past it by May 11, and one in ten still has one after June 5. Planting tender crops after May 29 leaves a 30% risk of a frost on them, after June 1 20%, and after June 5 10%. The 12 days between the even-odds date and the one-in-ten date is the narrowest of the 68 Montana stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 15 in half of years, as early as September 1 one year in ten, and holds off past September 27 one year in ten. A hard freeze of 28°F follows 10 days later, around September 25; in spring the one-in-ten date for 28°F is May 24, 12 days before the 32°F one. The freeze-free season lasts 113 days in a typical year, shorter than at 74% of the 68 Montana stations; it reaches 131 days one year in ten and falls short of 92 one year in ten. On average 186 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 22 and April 10.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | May 11 | May 15 | May 18 | May 21 | May 24 | May 26 | May 29 | Jun 1 | Jun 5 |
| 28°F | Apr 29 | May 2 | May 5 | May 9 | May 11 | May 13 | May 16 | May 19 | May 24 |
| 24°F | Apr 16 | Apr 22 | Apr 26 | Apr 29 | May 1 | May 4 | May 6 | May 10 | May 15 |
| 20°F | Apr 4 | Apr 10 | Apr 14 | Apr 17 | Apr 21 | Apr 24 | Apr 28 | May 1 | May 6 |
| 16°F | Mar 23 | Mar 31 | Apr 3 | Apr 7 | Apr 10 | Apr 13 | Apr 17 | Apr 21 | Apr 27 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Sep 1 | Sep 6 | Sep 10 | Sep 12 | Sep 15 | Sep 17 | Sep 20 | Sep 23 | Sep 27 |
| 28°F | Sep 11 | Sep 16 | Sep 20 | Sep 22 | Sep 25 | Sep 28 | Sep 30 | Oct 2 | Oct 6 |
| 24°F | Sep 20 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 10 | Oct 14 | Oct 18 |
| 20°F | Sep 30 | Oct 3 | Oct 6 | Oct 10 | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 29 |
| 16°F | Oct 3 | Oct 10 | Oct 15 | Oct 18 | Oct 22 | Oct 26 | Oct 29 | Nov 2 | Nov 7 |
Freeze probabilities 1991–2020 at Cut Bank Municipal Airport, MT, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 59427 →Compare Cut Bank with another place →
Weather by month in Cut Bank
July is the warmest month at Cut Bank Municipal Airport, MT, averaging 80°F by day and 50°F at night; January is the coldest at 32°F and 11°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 19% of years.
Warmth for growing adds up to 1,472 growing degree days a year (base 50°F), fewer than at 87% of the 68 Montana stations. 24% of them (347) have built up by the end of June, and July adds the most, 463. Precipitation totals 10.9 inches a year, most in June (2.7") and least in January (0.2"); May to September bring 72% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 32 | 11 | 0.2 | 100% | 28 | 0 |
| Feb | 34 | 12 | 0.2 | 100% | 26 | 1 |
| Mar | 43 | 20 | 0.4 | 100% | 27 | 2 |
| Apr | 52 | 28 | 1.0 | 100% | 21 | 13 |
| May | 62 | 37 | 1.7 | 99% | 8 | 95 |
| Jun | 70 | 45 | 2.7 | 19% | <1 | 237 |
| Jul | 80 | 50 | 1.3 | 2% | 0 | 463 |
| Aug | 80 | 48 | 1.0 | 8% | <1 | 434 |
| Sep | 69 | 40 | 1.1 | 96% | 4 | 183 |
| Oct | 54 | 30 | 0.6 | 100% | 18 | 40 |
| Nov | 41 | 20 | 0.4 | 100% | 24 | 4 |
| Dec | 33 | 13 | 0.3 | 100% | 29 | 0 |
Monthly normals 1991–2020 at Cut Bank Municipal Airport, MT (3,838 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Shelby, MT, 30 miles east of Cut Bank and 513 feet lower, has a last frost 1 day earlier (May 23), a first frost 1 day later (September 16), a season 2 days longer.
When it snows in Cut Bank, Montana
The first measurable snow (0.1 inch or more) in Cut Bank usually arrives around October 9, and the last of the season around April 28. Those are the middle dates across the winters of 1991–2020 at Del Bonita, MT, 26.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 26 days after the last snow.
Planting calendar for 59427
| When | What to do |
|---|---|
| March 15 – March 29 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 29 – April 12 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 26 – May 10 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 24 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 23 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 1 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 15 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 59427 is 7 miles from Cut Bank Municipal Airport, MT, which stands at 3,838 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 59427 in zone 4a, the band where the coldest night of the year averaged -30 to -25°F (-34.4 to -31.7°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.