Ashley climate

Ashley Frost Dates and Growing Season

NOAA 1991-2020 normals for Ashley, 0.8 km from Ashley, elevation 2014 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ashley. 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 13 and the first fall freeze around September 28, a growing season of about 137 days.

Median at 36°F
last May 21, first September 20
Median at 32°F
last May 13, first September 28
Median at 28°F
last May 5, 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°FJun 3May 30May 27May 24May 21May 19May 16May 13May 9
32°FMay 26May 21May 18May 15May 13May 10May 7May 4May 1
28°FMay 17May 13May 10May 7May 5May 2Apr 30Apr 26Apr 20
24°FMay 10May 5May 2Apr 29Apr 26Apr 22Apr 19Apr 15Apr 10
20°FMay 2Apr 27Apr 23Apr 19Apr 16Apr 13Apr 10Apr 7Apr 2
16°FApr 24Apr 17Apr 13Apr 10Apr 8Apr 4Apr 2Mar 29Mar 22

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 6Sep 11Sep 14Sep 17Sep 20Sep 23Sep 25Sep 27Oct 1
32°FSep 15Sep 19Sep 23Sep 25Sep 28Sep 30Oct 2Oct 5Oct 10
28°FSep 22Sep 26Sep 29Oct 1Oct 4Oct 7Oct 11Oct 14Oct 19
24°FSep 29Oct 3Oct 7Oct 10Oct 13Oct 16Oct 20Oct 23Oct 27
20°FOct 6Oct 11Oct 15Oct 19Oct 22Oct 25Oct 28Nov 1Nov 6
16°FOct 14Oct 21Oct 25Oct 29Nov 1Nov 3Nov 7Nov 11Nov 17

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°F137132127123120116112107100
32°F154148143140137133129125119
28°F172165161157153149145140134
24°F189182177173169165160156148
20°F208202195191187182178173166
16°F227220215210206202197192183

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
9,031
Cooling degree days, base 65°F
424
Growing degree days, base 40°F
3,874
Growing degree days, base 45°F
2,951
Growing degree days, base 50°F
2,134
Growing degree days, base 55°F
1,435
Growing degree days, base 60°F
855

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,68500
February1,40300
March1,18303
April732031
May36513185
June10170421
July28172609
August46133552
September23736277
October669154
November1,08802
December1,49600

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 0.8 km from Ashley. 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 USC00320382 (Ashley). Public domain.