Alden climate

Alden Frost Dates and Growing Season

NOAA 1991-2020 normals for Wells, 15.5 km from Alden, elevation 1135 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wells. 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 April 30 and the first fall freeze around October 6, a growing season of about 158 days.

Median at 36°F
last May 10, first September 29
Median at 32°F
last April 30, first October 6
Median at 28°F
last April 20, first October 17

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 24May 19May 15May 13May 10May 8May 5May 2Apr 28
32°FMay 14May 9May 6May 3Apr 30Apr 28Apr 25Apr 21Apr 16
28°FMay 6Apr 30Apr 27Apr 23Apr 20Apr 17Apr 14Apr 10Apr 5
24°FApr 26Apr 21Apr 18Apr 14Apr 10Apr 7Apr 5Apr 2Mar 26
20°FApr 19Apr 13Apr 9Apr 6Apr 3Mar 31Mar 28Mar 23Mar 17
16°FApr 11Apr 6Apr 2Mar 31Mar 26Mar 22Mar 18Mar 15Mar 10

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 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 4Oct 7Oct 11
32°FSep 24Sep 28Oct 1Oct 3Oct 6Oct 9Oct 12Oct 16Oct 20
28°FOct 1Oct 5Oct 10Oct 14Oct 17Oct 20Oct 23Oct 26Oct 31
24°FOct 12Oct 18Oct 21Oct 24Oct 27Oct 30Nov 1Nov 5Nov 11
20°FOct 23Oct 28Nov 1Nov 2Nov 5Nov 8Nov 11Nov 16Nov 21
16°FNov 1Nov 3Nov 7Nov 10Nov 12Nov 16Nov 19Nov 22Nov 28

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°F158152148144141137132127120
32°F178171166162158154151146139
28°F197190185181177173168164158
24°F219211206201197192188183175
20°F237229222218215211207201193
16°F255246241236231226222216210

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
7,753
Cooling degree days, base 65°F
668
Growing degree days, base 40°F
4,672
Growing degree days, base 45°F
3,644
Growing degree days, base 50°F
2,720
Growing degree days, base 55°F
1,913
Growing degree days, base 60°F
1,225

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,57300
February1,28400
March1,022012
April585369
May24439286
June42156564
July9226682
August23164606
September15072383
October5158109
November938010
December1,37000

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 15.5 km from Alden. 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 USC00218808 (Wells). Public domain.