Turtle Lake climate

Turtle Lake Frost Dates and Growing Season

NOAA 1991-2020 normals for Cumberland, 18.1 km from Turtle Lake, elevation 1240 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cumberland. 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 5 and the first fall freeze around October 4, a growing season of about 152 days.

Median at 36°F
last May 14, first September 27
Median at 32°F
last May 5, first October 4
Median at 28°F
last April 25, first October 16

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°FMay 29May 23May 20May 17May 14May 11May 9May 6May 3
32°FMay 18May 12May 9May 7May 5May 2Apr 30Apr 27Apr 22
28°FMay 8May 3Apr 30Apr 28Apr 25Apr 23Apr 20Apr 17Apr 12
24°FApr 27Apr 24Apr 21Apr 18Apr 16Apr 13Apr 11Apr 7Apr 4
20°FApr 21Apr 16Apr 13Apr 10Apr 8Apr 5Apr 3Apr 1Mar 27
16°FApr 14Apr 10Apr 7Apr 4Apr 2Mar 31Mar 29Mar 24Mar 18

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°FSep 15Sep 19Sep 22Sep 25Sep 27Sep 29Oct 1Oct 4Oct 8
32°FSep 23Sep 27Sep 30Oct 1Oct 4Oct 7Oct 10Oct 14Oct 19
28°FOct 1Oct 6Oct 10Oct 13Oct 16Oct 19Oct 22Oct 25Oct 30
24°FOct 13Oct 18Oct 22Oct 24Oct 28Oct 30Nov 1Nov 5Nov 10
20°FOct 24Oct 29Nov 1Nov 3Nov 6Nov 8Nov 11Nov 14Nov 19
16°FOct 31Nov 4Nov 7Nov 10Nov 12Nov 15Nov 18Nov 22Nov 25

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°F150145141137134130127122116
32°F169164159155152148145140134
28°F192186181176172168165160155
24°F215208203198195191187183177
20°F228223218215211208204200194
16°F244236232227224221217212206

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
8,984
Cooling degree days, base 65°F
378
Growing degree days, base 40°F
3,872
Growing degree days, base 45°F
2,937
Growing degree days, base 50°F
2,114
Growing degree days, base 55°F
1,403
Growing degree days, base 60°F
819

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,71400
February1,44200
March1,20003
April720030
May34414188
June8478445
July21152595
August41106530
September22928271
October635149
November1,05002
December1,50400

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 18.1 km from Turtle Lake. 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 USC00471923 (Cumberland). Public domain.