Alexander County climate

Alexander County Frost Dates and Growing Season

NOAA 1991-2020 normals for Cape Girardeau Muni AP, 20.9 km from Alexander County, elevation 336 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cape Girardeau Muni AP. 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 5 and the first fall freeze around October 25, a growing season of about 201 days.

Median at 36°F
last April 17, first October 16
Median at 32°F
last April 5, first October 25
Median at 28°F
last March 26, first November 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°FMay 1Apr 26Apr 23Apr 20Apr 17Apr 14Apr 11Apr 7Apr 2
32°FApr 21Apr 16Apr 12Apr 9Apr 5Apr 1Mar 30Mar 26Mar 19
28°FApr 11Apr 6Apr 1Mar 30Mar 26Mar 22Mar 18Mar 14Mar 7
24°FApr 2Mar 27Mar 21Mar 18Mar 14Mar 10Mar 6Mar 2Feb 24
20°FMar 21Mar 15Mar 11Mar 6Mar 3Feb 28Feb 23Feb 17Feb 6
16°FMar 13Mar 5Mar 1Feb 24Feb 19Feb 12Feb 6Feb 1Jan 21

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 2Oct 6Oct 10Oct 13Oct 16Oct 18Oct 20Oct 23Oct 28
32°FOct 12Oct 17Oct 20Oct 23Oct 25Oct 28Oct 31Nov 2Nov 6
28°FOct 23Oct 27Oct 31Nov 2Nov 4Nov 6Nov 10Nov 14Nov 21
24°FNov 2Nov 6Nov 9Nov 13Nov 16Nov 21Nov 25Dec 1Dec 7
20°FNov 12Nov 17Nov 22Nov 28Dec 1Dec 5Dec 10Dec 18Dec 25
16°FNov 23Dec 1Dec 6Dec 12Dec 17Dec 22Dec 28Jan 1Jan 11

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°F199193189184181176172167161
32°F223216211207201197193189182
28°F249240234229223218213208200
24°F274265260254249243238231224
20°F304293285278272267261253245
16°F332321312306300292285277265

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
4,177
Cooling degree days, base 65°F
1,566
Growing degree days, base 40°F
7,107
Growing degree days, base 45°F
5,712
Growing degree days, base 50°F
4,462
Growing degree days, base 55°F
3,356
Growing degree days, base 60°F
2,391

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January942011
February730021
March541494
April24229266
May60147552
June2340787
July0442907
August1383848
September37179593
October23839290
November550375
December835018

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 20.9 km from Alexander County. 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 USW00003935 (Cape Girardeau Muni AP). Public domain.