Lawrence County climate

Lawrence County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mt Vernon Univ Mo - Sw Ctr, 5.5 km from Lawrence County, elevation 1190 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mt Vernon Univ Mo - Sw Ctr. 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 14 and the first fall freeze around October 21, a growing season of about 188 days.

Median at 36°F
last April 27, first October 10
Median at 32°F
last April 14, first October 21
Median at 28°F
last April 3, first October 30

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 10May 5May 2Apr 30Apr 27Apr 23Apr 19Apr 16Apr 10
32°FMay 1Apr 26Apr 22Apr 18Apr 14Apr 10Apr 6Apr 3Mar 29
28°FApr 20Apr 14Apr 9Apr 6Apr 3Mar 30Mar 27Mar 22Mar 16
24°FApr 9Apr 3Mar 30Mar 27Mar 23Mar 18Mar 15Mar 10Mar 4
20°FMar 29Mar 22Mar 18Mar 14Mar 10Mar 6Mar 3Feb 28Feb 22
16°FMar 17Mar 12Mar 7Mar 4Mar 1Feb 26Feb 21Feb 16Feb 8

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 27Oct 1Oct 4Oct 7Oct 10Oct 12Oct 16Oct 19Oct 24
32°FOct 6Oct 12Oct 15Oct 18Oct 21Oct 23Oct 26Oct 29Nov 2
28°FOct 17Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 13
24°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15Nov 20Nov 27
20°FNov 1Nov 6Nov 11Nov 14Nov 18Nov 23Nov 29Dec 2Dec 9
16°FNov 9Nov 16Nov 22Nov 27Dec 1Dec 4Dec 9Dec 15Dec 22

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°F186178173168165161157152146
32°F211203198193188184179174165
28°F234226220215212207202196188
24°F256248243237232227222216208
20°F280272265259254248243237226
16°F305294288283277272266259250

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
4,493
Cooling degree days, base 65°F
1,411
Growing degree days, base 40°F
6,784
Growing degree days, base 45°F
5,425
Growing degree days, base 50°F
4,209
Growing degree days, base 55°F
3,132
Growing degree days, base 60°F
2,197

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January98908
February771020
March574596
April29526235
May101102469
June10278718
July1412876
August3378840
September51175576
October25832276
November567380
December874016

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 5.5 km from Lawrence 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 USC00235862 (Mt Vernon Univ Mo - Sw Ctr). Public domain.