Browning climate

Browning Frost Dates and Growing Season

NOAA 1991-2020 normals for E Glacier, 19.7 km from Browning, elevation 4806 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for E Glacier. 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 June 8 and the first fall freeze around September 5, a growing season of about 88 days.

Median at 32°F
last June 8, first September 5
Median at 28°F
last May 21, first September 23

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°FJul 1Jun 22Jun 17Jun 13Jun 8Jun 4Jun 1May 29May 24
28°FJun 7May 31May 28May 24May 21May 18May 15May 12May 7
24°FMay 24May 16May 12May 8May 6May 3Apr 30Apr 27Apr 20
20°FMay 11May 4Apr 30Apr 28Apr 24Apr 20Apr 17Apr 12Apr 5
16°FApr 29Apr 24Apr 19Apr 16Apr 12Apr 8Apr 5Apr 2Mar 27

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°FAug 20Aug 27Aug 31Sep 2Sep 5Sep 8Sep 11Sep 15Sep 20
28°FSep 4Sep 12Sep 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 5
24°FSep 21Sep 27Sep 30Oct 2Oct 5Oct 8Oct 12Oct 16Oct 21
20°FSep 30Oct 3Oct 8Oct 12Oct 16Oct 18Oct 23Oct 28Nov 1
16°FOct 5Oct 12Oct 17Oct 21Oct 25Oct 29Nov 1Nov 5Nov 10

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°F756862575247413529
32°F11010397938883787060
28°F14413713112612211811210596
24°F174167161156153149143136127
20°F200191185179175170165158152
16°F222212205200195190184178170

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
9,569
Cooling degree days, base 65°F
39
Growing degree days, base 40°F
2,318
Growing degree days, base 45°F
1,528
Growing degree days, base 50°F
903
Growing degree days, base 55°F
450
Growing degree days, base 60°F
170

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,34100
February1,21100
March1,14700
April86903
May622041
June3712122
July17921312
August19515297
September4361107
October786019
November1,07901
December1,33500

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 19.7 km from Browning. 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 USC00242629 (E Glacier). Public domain.