Aberdeen climate

Aberdeen Frost Dates and Growing Season

NOAA 1991-2020 normals for Aberdeen Exp Stn, 1.5 km from Aberdeen, elevation 4405 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Aberdeen Exp Stn. 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 21 and the first fall freeze around September 20, a growing season of about 118 days.

Median at 36°F
last June 12, first September 5
Median at 32°F
last May 21, first September 20
Median at 28°F
last May 3, first October 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°FJun 28Jun 23Jun 19Jun 16Jun 12Jun 9Jun 4May 31May 23
32°FJun 13Jun 5May 31May 26May 21May 16May 13May 9May 4
28°FMay 17May 12May 8May 5May 3Apr 30Apr 28Apr 26Apr 20
24°FMay 5Apr 30Apr 27Apr 24Apr 21Apr 18Apr 15Apr 11Apr 6
20°FApr 25Apr 20Apr 16Apr 12Apr 7Apr 4Mar 31Mar 23Mar 14
16°FApr 10Apr 4Mar 30Mar 18Mar 13Mar 10Mar 7Mar 4Feb 27

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°FAug 21Aug 27Aug 31Sep 3Sep 5Sep 9Sep 13Sep 17Sep 22
32°FSep 2Sep 8Sep 13Sep 17Sep 20Sep 22Sep 26Sep 29Oct 4
28°FSep 15Sep 20Sep 24Sep 28Oct 1Oct 4Oct 7Oct 12Oct 17
24°FSep 27Oct 3Oct 6Oct 11Oct 14Oct 17Oct 21Oct 24Oct 31
20°FOct 11Oct 17Oct 21Oct 25Oct 28Oct 31Nov 2Nov 6Nov 13
16°FOct 22Oct 27Nov 1Nov 2Nov 6Nov 10Nov 15Nov 20Nov 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°F11010194908581767063
32°F14113312812311811310710191
28°F170163158153149145141136127
24°F198189183180175170165160153
20°F231221214208202197192186177
16°F261253248242236230223215204

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
7,455
Cooling degree days, base 65°F
346
Growing degree days, base 40°F
3,854
Growing degree days, base 45°F
2,848
Growing degree days, base 50°F
2,006
Growing degree days, base 55°F
1,311
Growing degree days, base 60°F
754

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30200
February1,05600
March87002
April620027
May3546165
June15142347
July27154592
August39125551
September21719271
October596049
November94802
December1,27600

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 1.5 km from Aberdeen. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00100010 (Aberdeen Exp Stn). Public domain.