Watkins climate

Watkins Frost Dates and Growing Season

NOAA 1991-2020 normals for Kimball 3N, 9.1 km from Watkins, elevation 1160 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kimball 3N. 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 2 and the first fall freeze around October 5, a growing season of about 156 days.

Median at 36°F
last May 11, first September 27
Median at 32°F
last May 2, first October 5
Median at 28°F
last April 23, first October 19

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 27May 21May 17May 14May 11May 8May 6May 3Apr 30
32°FMay 15May 9May 7May 4May 2Apr 30Apr 28Apr 24Apr 19
28°FMay 5May 1Apr 29Apr 26Apr 23Apr 20Apr 17Apr 13Apr 8
24°FApr 27Apr 22Apr 18Apr 16Apr 13Apr 10Apr 7Apr 4Apr 1
20°FApr 19Apr 14Apr 10Apr 7Apr 5Apr 3Apr 1Mar 28Mar 22
16°FApr 12Apr 6Apr 3Apr 1Mar 30Mar 26Mar 22Mar 19Mar 14

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 14Sep 19Sep 22Sep 24Sep 27Sep 30Oct 2Oct 5Oct 10
32°FSep 23Sep 27Sep 30Oct 2Oct 5Oct 9Oct 12Oct 16Oct 21
28°FOct 1Oct 7Oct 11Oct 16Oct 19Oct 22Oct 25Oct 29Nov 2
24°FOct 16Oct 21Oct 24Oct 28Oct 30Nov 1Nov 4Nov 7Nov 12
20°FOct 25Oct 30Nov 1Nov 3Nov 6Nov 8Nov 11Nov 14Nov 19
16°FNov 1Nov 5Nov 7Nov 10Nov 13Nov 15Nov 18Nov 22Nov 27

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°F155149145140136132128125119
32°F176168163159156152148143136
28°F197191186181177173168164158
24°F219212206202198195191186179
20°F234227223219215212207203196
16°F248242237232228225221216210

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
8,555
Cooling degree days, base 65°F
405
Growing degree days, base 40°F
4,100
Growing degree days, base 45°F
3,121
Growing degree days, base 50°F
2,254
Growing degree days, base 55°F
1,508
Growing degree days, base 60°F
883

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,66700
February1,38600
March1,14906
April674139
May31118212
June6880463
July15158607
August36110539
September19337307
October578377
November1,02204
December1,45700

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 9.1 km from Watkins. 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 USC00214373 (Kimball 3N). Public domain.