Aberdeen climate

Aberdeen Frost Dates and Growing Season

NOAA 1991-2020 normals for Aberdeen, 5.8 km from Aberdeen, elevation 1302 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Aberdeen. 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 9 and the first fall freeze around September 26, a growing season of about 139 days.

Median at 36°F
last May 19, first September 17
Median at 32°F
last May 9, first September 26
Median at 28°F
last April 30, first October 4

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 31May 27May 24May 22May 19May 16May 13May 10May 6
32°FMay 22May 18May 14May 11May 9May 6May 4Apr 30Apr 27
28°FMay 13May 8May 5May 3Apr 30Apr 28Apr 25Apr 20Apr 16
24°FMay 5May 1Apr 28Apr 23Apr 20Apr 18Apr 15Apr 12Apr 7
20°FApr 28Apr 22Apr 18Apr 15Apr 11Apr 8Apr 6Apr 3Mar 31
16°FApr 18Apr 13Apr 10Apr 6Apr 4Apr 1Mar 30Mar 24Mar 17

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 4Sep 8Sep 11Sep 14Sep 17Sep 20Sep 22Sep 25Sep 29
32°FSep 14Sep 18Sep 21Sep 24Sep 26Sep 28Oct 1Oct 4Oct 7
28°FSep 23Sep 27Sep 29Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18
24°FSep 30Oct 3Oct 8Oct 11Oct 14Oct 17Oct 20Oct 23Oct 27
20°FOct 8Oct 15Oct 19Oct 22Oct 24Oct 27Oct 30Nov 2Nov 6
16°FOct 19Oct 24Oct 28Oct 31Nov 1Nov 4Nov 6Nov 10Nov 15

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°F139133128124121117114110103
32°F157151146143139135132127122
28°F176170166161156153149145139
24°F196189185179175171167162154
20°F215208204199195191187181173
16°F231224219214210207203198192

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
8,222
Cooling degree days, base 65°F
630
Growing degree days, base 40°F
4,452
Growing degree days, base 45°F
3,456
Growing degree days, base 50°F
2,569
Growing degree days, base 55°F
1,798
Growing degree days, base 60°F
1,150

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,61800
February1,33100
March1,06806
April616152
May26831262
June51130530
July10237691
August26172611
September18056338
October583475
November1,02204
December1,44800

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 5.8 km from Aberdeen. 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 USW00014929 (Aberdeen). Public domain.