Red Bud climate

Red Bud Frost Dates and Growing Season

NOAA 1991-2020 normals for Kaskaskia Rvr Navigation Lock, 25.8 km from Red Bud, elevation 380 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kaskaskia Rvr Navigation Lock. 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 8 and the first fall freeze around October 30, a growing season of about 202 days.

Median at 36°F
last April 20, first October 18
Median at 32°F
last April 8, first October 30
Median at 28°F
last March 28, 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°FMay 5Apr 30Apr 26Apr 23Apr 20Apr 17Apr 14Apr 10Apr 5
32°FApr 25Apr 19Apr 15Apr 11Apr 8Apr 5Apr 2Mar 29Mar 22
28°FApr 13Apr 7Apr 3Mar 31Mar 28Mar 23Mar 19Mar 15Mar 9
24°FApr 2Mar 27Mar 22Mar 18Mar 14Mar 10Mar 7Mar 3Feb 26
20°FMar 22Mar 16Mar 12Mar 8Mar 4Mar 1Feb 26Feb 20Feb 9
16°FMar 14Mar 8Mar 4Feb 28Feb 24Feb 18Feb 11Feb 5Jan 30

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 18Oct 20Oct 23Oct 27Oct 31
32°FOct 15Oct 20Oct 24Oct 28Oct 30Nov 1Nov 4Nov 8Nov 13
28°FOct 27Nov 1Nov 3Nov 6Nov 10Nov 13Nov 18Nov 23Nov 30
24°FNov 5Nov 12Nov 16Nov 20Nov 24Nov 28Dec 1Dec 5Dec 12
20°FNov 16Nov 23Nov 28Dec 1Dec 4Dec 8Dec 13Dec 18Dec 24
16°FNov 27Dec 1Dec 7Dec 11Dec 16Dec 21Dec 26Dec 30Jan 7

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°F200193188182179175170165159
32°F226218212207202198193187180
28°F256248240234228224219213204
24°F280272265259254249244237228
20°F304295288282277271265259249
16°F326316308303298292287279270

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
4,576
Cooling degree days, base 65°F
1,461
Growing degree days, base 40°F
6,780
Growing degree days, base 45°F
5,430
Growing degree days, base 50°F
4,230
Growing degree days, base 55°F
3,171
Growing degree days, base 60°F
2,247

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,01707
February798015
March606375
April29822222
May89119496
June5308753
July0425890
August2364828
September43180587
October25637276
November571270
December891012

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 25.8 km from Red Bud. 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 USC00114629 (Kaskaskia Rvr Navigation Lock). Public domain.