Amidon climate

Amidon Frost Dates and Growing Season

NOAA 1991-2020 normals for Amidon, 0 km from Amidon, elevation 2910 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Amidon. 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 12 and the first fall freeze around September 29, a growing season of about 136 days.

Median at 36°F
last May 24, first September 19
Median at 32°F
last May 12, first September 29
Median at 28°F
last May 3, first October 6

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

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 5Sep 10Sep 13Sep 17Sep 19Sep 22Sep 24Sep 27Oct 1
32°FSep 14Sep 20Sep 23Sep 26Sep 29Oct 1Oct 3Oct 6Oct 10
28°FSep 23Sep 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 16Oct 20
24°FOct 1Oct 6Oct 10Oct 13Oct 16Oct 18Oct 21Oct 25Oct 30
20°FOct 8Oct 14Oct 18Oct 22Oct 25Oct 27Oct 31Nov 3Nov 9
16°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 4Nov 9Nov 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°F13512912512111711410910498
32°F154148143139136132128124116
28°F175169163158154150146141134
24°F196188184179175171165159152
20°F216209203198193190185180173
16°F235226220215212208203197190

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
7,995
Cooling degree days, base 65°F
554
Growing degree days, base 40°F
4,201
Growing degree days, base 45°F
3,208
Growing degree days, base 50°F
2,346
Growing degree days, base 55°F
1,612
Growing degree days, base 60°F
1,011

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,46200
February1,19301
March1,02007
April649146
May36110180
June11273414
July25216656
August34194626
September20257330
October613377
November98309
December1,34100

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 km from Amidon. 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 USC00320209 (Amidon). Public domain.