Perry climate

Perry Frost Dates and Growing Season

NOAA 1991-2020 normals for Perry Lake, 4.8 km from Perry, elevation 957 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Perry Lake. 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 13 and the first fall freeze around October 24, a growing season of about 191 days.

Median at 36°F
last April 25, first October 14
Median at 32°F
last April 13, first October 24
Median at 28°F
last April 3, first November 2

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 8May 4Apr 30Apr 28Apr 25Apr 22Apr 19Apr 15Apr 10
32°FApr 30Apr 23Apr 20Apr 16Apr 13Apr 10Apr 8Apr 4Mar 31
28°FApr 18Apr 12Apr 9Apr 6Apr 3Mar 31Mar 28Mar 23Mar 15
24°FApr 8Apr 2Mar 30Mar 27Mar 23Mar 20Mar 15Mar 10Mar 4
20°FMar 30Mar 24Mar 20Mar 16Mar 11Mar 7Mar 4Mar 1Feb 24
16°FMar 19Mar 14Mar 9Mar 6Mar 3Mar 1Feb 26Feb 21Feb 14

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 30Oct 4Oct 8Oct 12Oct 14Oct 17Oct 20Oct 23Oct 27
32°FOct 9Oct 16Oct 19Oct 22Oct 24Oct 26Oct 29Nov 1Nov 6
28°FOct 20Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 13Nov 19
24°FOct 28Nov 1Nov 5Nov 8Nov 13Nov 16Nov 20Nov 25Nov 30
20°FNov 4Nov 10Nov 14Nov 18Nov 22Nov 26Nov 30Dec 4Dec 10
16°FNov 13Nov 20Nov 25Nov 29Dec 1Dec 5Dec 9Dec 14Dec 20

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°F190184179175172167163158151
32°F211204200196191187183178170
28°F237229223218214210205200193
24°F258251244239235231226220212
20°F280271265260254250244237229
16°F299290284278273268263256246

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
5,321
Cooling degree days, base 65°F
1,277
Growing degree days, base 40°F
6,240
Growing degree days, base 45°F
4,982
Growing degree days, base 50°F
3,855
Growing degree days, base 55°F
2,863
Growing degree days, base 60°F
2,005

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16102
February91107
March675260
April36514175
May12982424
June10258697
July1396860
August3350812
September67148533
October31025235
November670147
December1,01804

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 4.8 km from Perry. 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 USC00146333 (Perry Lake). Public domain.