Cut Bank climate

Cut Bank Frost Dates and Growing Season

NOAA 1991-2020 normals for Cut Bank Muni AP, 4.9 km from Cut Bank, elevation 3838 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cut Bank Muni AP. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around May 24 and the first fall freeze around September 15, a growing season of about 113 days.

Median at 32°F
last May 24, first September 15
Median at 28°F
last May 11, first September 25

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°F–––––––––
32°FJun 5Jun 1May 29May 26May 24May 21May 18May 15May 11
28°FMay 24May 19May 16May 13May 11May 9May 5May 2Apr 29
24°FMay 15May 10May 6May 4May 1Apr 29Apr 26Apr 22Apr 16
20°FMay 6May 1Apr 28Apr 24Apr 21Apr 17Apr 14Apr 10Apr 4
16°FApr 27Apr 21Apr 17Apr 13Apr 10Apr 7Apr 3Mar 31Mar 23

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°F–––––––––
32°FSep 1Sep 6Sep 10Sep 12Sep 15Sep 17Sep 20Sep 23Sep 27
28°FSep 11Sep 16Sep 20Sep 22Sep 25Sep 28Sep 30Oct 2Oct 6
24°FSep 20Sep 26Sep 29Oct 1Oct 4Oct 6Oct 10Oct 14Oct 18
20°FSep 30Oct 3Oct 6Oct 10Oct 13Oct 17Oct 20Oct 24Oct 29
16°FOct 3Oct 10Oct 15Oct 18Oct 22Oct 26Oct 29Nov 2Nov 7

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F1039791878277726556
32°F13112512111611310910610092
28°F154148144140136133128124117
24°F173167163159154151147143136
20°F197189183178173169165159153
16°F219210204199194189183177171

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
8,579
Cooling degree days, base 65°F
164
Growing degree days, base 40°F
3,173
Growing degree days, base 45°F
2,234
Growing degree days, base 50°F
1,472
Growing degree days, base 55°F
868
Growing degree days, base 60°F
433

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33900
February1,17301
March1,04902
April744013
May477195
June23511237
July7976463
August10267434
September3268183
October712140
November1,03204
December1,31000

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 4.9 km from Cut Bank. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00024137 (Cut Bank Muni AP). Public domain.