Linn climate

Linn Frost Dates and Growing Season

NOAA 1991-2020 normals for Mccook, 0.6 km from Linn, elevation 220 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mccook. 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 January 22 and the first fall freeze around December 19, a growing season of about 333 days.

Median at 36°F
last February 18, first December 4
Median at 32°F
last January 22, first December 19
Median at 28°F
last January 6, first January 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°FMar 13Mar 7Mar 1Feb 24Feb 18Feb 10Feb 1Jan 23Jan 11
32°FMar 5Feb 22Feb 12Jan 31Jan 22Jan 16Jan 7Dec 30Dec 19
28°FFeb 16Jan 31Jan 19Jan 12Jan 6Jan 2Dec 28Dec 22Dec 11
24°FJan 23Jan 13Jan 7Jan 3Dec 30Dec 26Dec 21Dec 15Dec 11
20°F–––––––––
16°F–––––––––

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°FNov 13Nov 20Nov 26Dec 1Dec 4Dec 8Dec 13Dec 22Jan 1
32°FNov 26Dec 3Dec 7Dec 12Dec 19Dec 26Jan 1Jan 9Jan 23
28°FDec 5Dec 11Dec 19Dec 26Jan 1Jan 4Jan 10Jan 18Feb 3
24°FDec 10Dec 14Dec 19Dec 24Dec 27Jan 1Jan 5Jan 9Jan 20
20°F–––––––––
16°F–––––––––

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°F334319308300292285277268258
32°F365358348340333324312303287
28°F365365365365365358351341330
24°F365365365365365365365365355
20°F365365365365365365365365365
16°F365365365365365365365365365

How often it gets that cold

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

36°F or colder
99% of years
32°F or colder
86% of years
28°F or colder
48% of years
24°F or colder
15% of years
20°F or colder
4% of years
16°F or colder
1% 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
813
Cooling degree days, base 65°F
3,881
Growing degree days, base 40°F
12,201
Growing degree days, base 45°F
10,399
Growing degree days, base 50°F
8,634
Growing degree days, base 55°F
6,938
Growing degree days, base 60°F
5,345

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January25239289
February14375366
March63171578
April13291728
May1461925
June05791,029
July06391,104
August06451,110
September1484933
October12324777
November98126484
December23050312

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 0.6 km from Linn. 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 USC00415721 (Mccook). Public domain.