Arlington climate

Arlington Frost Dates and Growing Season

NOAA 1991-2020 normals for Arlington 1 W, 3 km from Arlington, elevation 1824 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Arlington 1 W. 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 3 and the first fall freeze around October 2, a growing season of about 151 days.

Median at 36°F
last May 13, first September 25
Median at 32°F
last May 3, first October 2
Median at 28°F
last April 25, first October 10

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 22May 18May 16May 13May 11May 8May 5May 1
32°FMay 15May 11May 8May 6May 3May 1Apr 29Apr 26Apr 21
28°FMay 7May 3Apr 30Apr 28Apr 25Apr 22Apr 19Apr 15Apr 10
24°FApr 29Apr 25Apr 21Apr 19Apr 16Apr 12Apr 9Apr 6Apr 2
20°FApr 22Apr 17Apr 13Apr 9Apr 7Apr 4Apr 1Mar 29Mar 22
16°FApr 16Apr 9Apr 5Apr 2Mar 31Mar 27Mar 23Mar 19Mar 13

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 12Sep 16Sep 20Sep 22Sep 25Sep 28Oct 1Oct 3Oct 6
32°FSep 19Sep 24Sep 28Sep 30Oct 2Oct 5Oct 7Oct 11Oct 16
28°FSep 27Oct 1Oct 4Oct 7Oct 10Oct 14Oct 17Oct 21Oct 27
24°FOct 5Oct 10Oct 15Oct 19Oct 21Oct 24Oct 28Nov 1Nov 5
20°FOct 15Oct 21Oct 25Oct 29Oct 31Nov 2Nov 5Nov 9Nov 14
16°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 17Nov 23

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°F152146141137134130127123118
32°F171163159154151147144140134
28°F190183178174170166161157151
24°F209202196192188184180175168
20°F228220215211207202197192185
16°F244236230226221217214208201

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
7,959
Cooling degree days, base 65°F
605
Growing degree days, base 40°F
4,503
Growing degree days, base 45°F
3,489
Growing degree days, base 50°F
2,585
Growing degree days, base 55°F
1,796
Growing degree days, base 60°F
1,130

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,56500
February1,28400
March1,04809
April605257
May25628266
June50125525
July13220673
August25165605
September16760356
October555488
November98307
December1,40900

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 3 km from Arlington. 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 USC00390281 (Arlington 1 W). Public domain.