Littlefork climate

Littlefork Frost Dates and Growing Season

NOAA 1991-2020 normals for Littlefork 10 Sw, 12.7 km from Littlefork, elevation 1200 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Littlefork 10 Sw. 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 23 and the first fall freeze around September 21, a growing season of about 118 days.

Median at 36°F
last June 4, first September 10
Median at 32°F
last May 23, first September 21
Median at 28°F
last May 10, first October 1

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°FJun 26Jun 18Jun 11Jun 7Jun 4Jun 1May 30May 26May 22
32°FJun 5May 31May 29May 26May 23May 21May 17May 14May 9
28°FMay 25May 20May 16May 13May 10May 7May 5May 2Apr 28
24°FMay 14May 9May 5May 2Apr 30Apr 28Apr 25Apr 22Apr 17
20°FMay 2Apr 29Apr 26Apr 22Apr 19Apr 17Apr 14Apr 11Apr 7
16°FApr 25Apr 20Apr 17Apr 14Apr 11Apr 8Apr 6Apr 3Mar 31

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°FAug 25Aug 31Sep 3Sep 6Sep 10Sep 13Sep 16Sep 20Sep 24
32°FSep 4Sep 10Sep 14Sep 17Sep 21Sep 23Sep 27Oct 1Oct 4
28°FSep 15Sep 20Sep 25Sep 28Oct 1Oct 3Oct 6Oct 10Oct 14
24°FSep 27Oct 2Oct 6Oct 9Oct 12Oct 15Oct 18Oct 21Oct 27
20°FOct 10Oct 15Oct 19Oct 23Oct 26Oct 29Nov 1Nov 4Nov 9
16°FOct 22Oct 27Oct 31Nov 2Nov 4Nov 7Nov 10Nov 13Nov 18

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°F1171101041009691857867
32°F14013212712211811411010497
28°F161155150146141138133127119
24°F185178172167163159155149141
20°F208202197192188184179174167
16°F224218212209205201198193186

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
10,105
Cooling degree days, base 65°F
221
Growing degree days, base 40°F
3,281
Growing degree days, base 45°F
2,413
Growing degree days, base 50°F
1,660
Growing degree days, base 55°F
1,032
Growing degree days, base 60°F
543

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,89400
February1,56900
March1,28501
April795018
May4208139
June14846354
July6690490
August9362435
September31714192
October723030
November1,15101
December1,64400

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 12.7 km from Littlefork. 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 USC00214809 (Littlefork 10 Sw). Public domain.