Valmeyer climate

Valmeyer Frost Dates and Growing Season

NOAA 1991-2020 normals for Festus, 13.4 km from Valmeyer, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Festus. 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 9 and the first fall freeze around October 26, a growing season of about 197 days.

Median at 36°F
last April 22, first October 17
Median at 32°F
last April 9, first October 26
Median at 28°F
last March 31, first November 5

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 2Apr 29Apr 25Apr 22Apr 19Apr 15Apr 11Apr 5
32°FApr 25Apr 20Apr 16Apr 13Apr 9Apr 6Apr 3Mar 31Mar 25
28°FApr 15Apr 9Apr 4Apr 2Mar 31Mar 26Mar 23Mar 19Mar 12
24°FApr 3Mar 29Mar 25Mar 22Mar 19Mar 15Mar 10Mar 7Mar 1
20°FMar 26Mar 20Mar 16Mar 12Mar 8Mar 5Mar 2Feb 26Feb 18
16°FMar 17Mar 11Mar 7Mar 3Mar 1Feb 25Feb 21Feb 14Feb 5

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 4Oct 9Oct 12Oct 15Oct 17Oct 19Oct 22Oct 24Oct 28
32°FOct 14Oct 19Oct 22Oct 24Oct 26Oct 29Oct 31Nov 3Nov 8
28°FOct 23Oct 28Nov 1Nov 3Nov 5Nov 8Nov 12Nov 16Nov 23
24°FNov 2Nov 6Nov 10Nov 14Nov 18Nov 22Nov 26Dec 1Dec 4
20°FNov 9Nov 16Nov 21Nov 26Nov 29Dec 1Dec 5Dec 10Dec 16
16°FNov 19Nov 26Dec 1Dec 4Dec 9Dec 13Dec 18Dec 23Dec 29

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°F195189182178174170166160153
32°F220212206201197193189183177
28°F246237231226221216212206197
24°F269260253248243238233227220
20°F291281275270265259254248239
16°F312303297291285280273266257

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
4,700
Cooling degree days, base 65°F
1,352
Growing degree days, base 40°F
6,614
Growing degree days, base 45°F
5,286
Growing degree days, base 50°F
4,095
Growing degree days, base 55°F
3,045
Growing degree days, base 60°F
2,128

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03408
February818017
March627576
April30125224
May104104468
June9267708
July0397862
August2352815
September48163566
October26736269
November586370
December905013

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 13.4 km from Valmeyer. 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 USC00232850 (Festus). Public domain.