Appanoose County climate

Appanoose County Frost Dates and Growing Season

NOAA 1991-2020 normals for Centerville, 2.1 km from Appanoose County, elevation 905 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Centerville. 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 28 and the first fall freeze around October 14, a growing season of about 168 days.

Median at 36°F
last May 7, first October 3
Median at 32°F
last April 28, first October 14
Median at 28°F
last April 17, first October 24

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 22May 17May 13May 10May 7May 5May 2Apr 30Apr 24
32°FMay 11May 6May 3May 1Apr 28Apr 25Apr 22Apr 18Apr 13
28°FMay 2Apr 27Apr 23Apr 20Apr 17Apr 13Apr 11Apr 7Apr 3
24°FApr 21Apr 16Apr 12Apr 9Apr 7Apr 4Apr 1Mar 28Mar 21
20°FApr 13Apr 7Apr 3Mar 31Mar 28Mar 25Mar 20Mar 16Mar 10
16°FApr 3Mar 29Mar 26Mar 21Mar 18Mar 14Mar 10Mar 6Mar 2

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 19Sep 23Sep 28Oct 1Oct 3Oct 6Oct 9Oct 13Oct 16
32°FSep 26Oct 2Oct 6Oct 10Oct 14Oct 17Oct 19Oct 22Oct 26
28°FOct 10Oct 16Oct 19Oct 21Oct 24Oct 27Oct 29Nov 1Nov 4
24°FOct 20Oct 25Oct 28Oct 30Nov 1Nov 3Nov 6Nov 9Nov 13
20°FOct 30Nov 1Nov 4Nov 6Nov 9Nov 11Nov 14Nov 18Nov 24
16°FNov 4Nov 8Nov 11Nov 15Nov 18Nov 21Nov 25Nov 29Dec 4

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°F167160155152148144139134127
32°F186180176172168164160155147
28°F206200196191188184181176169
24°F228221216212208204200196189
20°F249240235230225220216211205
16°F268260253248244239235229220

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
6,330
Cooling degree days, base 65°F
880
Growing degree days, base 40°F
5,359
Growing degree days, base 45°F
4,204
Growing degree days, base 50°F
3,175
Growing degree days, base 55°F
2,278
Growing degree days, base 60°F
1,510

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32200
February1,06803
March822132
April4566117
May19349335
June24183609
July2295758
August9244700
September11490431
October40012163
November777027
December1,14402

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 2.1 km from Appanoose County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00131354 (Centerville). Public domain.