Perry climate

Perry Frost Dates and Growing Season

NOAA 1991-2020 normals for Perry, 0.2 km from Perry, elevation 1025 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Perry. 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 4 and the first fall freeze around November 1, a growing season of about 210 days.

Median at 36°F
last April 16, first October 23
Median at 32°F
last April 4, first November 1
Median at 28°F
last March 25, first November 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°FApr 30Apr 25Apr 22Apr 19Apr 16Apr 13Apr 10Apr 6Apr 1
32°FApr 20Apr 15Apr 11Apr 7Apr 4Apr 1Mar 30Mar 25Mar 20
28°FApr 8Apr 4Mar 31Mar 29Mar 25Mar 22Mar 16Mar 11Mar 5
24°FMar 30Mar 23Mar 20Mar 15Mar 11Mar 7Mar 4Mar 1Feb 25
20°FMar 20Mar 12Mar 7Mar 4Mar 1Feb 26Feb 23Feb 17Feb 7
16°FMar 11Mar 5Mar 2Feb 26Feb 21Feb 16Feb 11Feb 2Jan 24

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°FOct 10Oct 15Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 5
32°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 3Nov 7Nov 11Nov 17
28°FOct 25Oct 31Nov 3Nov 7Nov 10Nov 14Nov 17Nov 21Nov 28
24°FNov 1Nov 8Nov 13Nov 17Nov 21Nov 24Nov 28Dec 2Dec 7
20°FNov 11Nov 19Nov 24Nov 28Dec 2Dec 6Dec 10Dec 16Dec 23
16°FNov 25Dec 1Dec 7Dec 12Dec 18Dec 23Dec 29Jan 3Jan 12

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°F211203198194190186182177172
32°F233225219214210206202197190
28°F256247241236232227222215208
24°F278269263257253248243236228
20°F304293287281276270265259249
16°F329319312305300294288279270

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
3,753
Cooling degree days, base 65°F
2,095
Growing degree days, base 40°F
7,955
Growing degree days, base 45°F
6,500
Growing degree days, base 50°F
5,191
Growing degree days, base 55°F
4,018
Growing degree days, base 60°F
2,988

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January873011
February678131
March4778135
April21342303
May44172594
June2412861
July05701,035
August0530995
September19285717
October16968379
November4776112
December803019

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 0.2 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 USC00347012 (Perry). Public domain.