Turtle Lake climate

Turtle Lake Frost Dates and Growing Season

NOAA 1991-2020 normals for Turtle Lake, 0.2 km from Turtle Lake, elevation 1893 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Turtle Lake. 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 14 and the first fall freeze around September 26, a growing season of about 136 days.

Median at 36°F
last May 24, first September 19
Median at 32°F
last May 14, first September 26
Median at 28°F
last May 5, first October 5

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 4May 31May 29May 26May 24May 21May 19May 15May 12
32°FMay 26May 22May 19May 17May 14May 12May 10May 7May 3
28°FMay 18May 13May 10May 8May 5May 2Apr 30Apr 26Apr 20
24°FMay 9May 5May 2Apr 30Apr 27Apr 22Apr 19Apr 15Apr 10
20°FMay 1Apr 26Apr 22Apr 18Apr 16Apr 13Apr 10Apr 6Apr 2
16°FApr 22Apr 17Apr 14Apr 11Apr 8Apr 5Apr 3Mar 31Mar 25

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 7Sep 11Sep 14Sep 17Sep 19Sep 21Sep 23Sep 25Sep 30
32°FSep 15Sep 19Sep 22Sep 24Sep 26Sep 28Oct 1Oct 4Oct 9
28°FSep 23Sep 26Sep 29Oct 2Oct 5Oct 9Oct 12Oct 15Oct 20
24°FOct 1Oct 5Oct 10Oct 13Oct 15Oct 18Oct 21Oct 24Oct 29
20°FOct 9Oct 14Oct 18Oct 22Oct 25Oct 28Oct 31Nov 3Nov 8
16°FOct 18Oct 23Oct 27Oct 31Nov 2Nov 5Nov 8Nov 12Nov 16

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°F133128125121118115111107101
32°F154147143139136133129125119
28°F172166162159155151146141136
24°F193186181176173169164160153
20°F210204199195191187183178170
16°F228221215211207204200195189

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
9,092
Cooling degree days, base 65°F
413
Growing degree days, base 40°F
3,849
Growing degree days, base 45°F
2,925
Growing degree days, base 50°F
2,112
Growing degree days, base 55°F
1,415
Growing degree days, base 60°F
841

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,68800
February1,41700
March1,19003
April729029
May36511179
June10465414
July27168606
August44137558
September24031270
October668151
November1,10102
December1,52000

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 0.2 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 USC00328840 (Turtle Lake). Public domain.