Nauvoo climate

Nauvoo Frost Dates and Growing Season

NOAA 1991-2020 normals for Ft Madison, 9.1 km from Nauvoo, elevation 530 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ft Madison. 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 12 and the first fall freeze around October 25, a growing season of about 194 days.

Median at 36°F
last April 24, first October 16
Median at 32°F
last April 12, first October 25
Median at 28°F
last April 3, 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 7May 4May 1Apr 27Apr 24Apr 21Apr 18Apr 14Apr 10
32°FApr 26Apr 22Apr 18Apr 15Apr 12Apr 10Apr 7Apr 4Apr 1
28°FApr 17Apr 11Apr 8Apr 5Apr 3Mar 31Mar 28Mar 24Mar 18
24°FApr 7Apr 3Mar 31Mar 27Mar 24Mar 20Mar 16Mar 12Mar 7
20°FMar 31Mar 25Mar 22Mar 18Mar 14Mar 11Mar 8Mar 4Feb 27
16°FMar 23Mar 17Mar 14Mar 10Mar 7Mar 4Mar 1Feb 25Feb 20

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 1Oct 6Oct 9Oct 13Oct 16Oct 18Oct 20Oct 23Oct 27
32°FOct 11Oct 17Oct 20Oct 23Oct 25Oct 27Oct 30Nov 2Nov 6
28°FOct 23Oct 27Oct 31Nov 1Nov 4Nov 6Nov 9Nov 12Nov 18
24°FNov 1Nov 4Nov 7Nov 9Nov 12Nov 15Nov 19Nov 24Nov 30
20°FNov 7Nov 11Nov 14Nov 18Nov 21Nov 25Nov 29Dec 3Dec 9
16°FNov 14Nov 20Nov 24Nov 27Dec 1Dec 4Dec 8Dec 12Dec 19

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°F192186181176173169165161155
32°F212206202198194191187181174
28°F234227222218215211206202196
24°F256248243238234229226221213
20°F276268262257253248243239231
16°F292284279274269265261256246

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
5,731
Cooling degree days, base 65°F
1,119
Growing degree days, base 40°F
5,887
Growing degree days, base 45°F
4,683
Growing degree days, base 50°F
3,602
Growing degree days, base 55°F
2,647
Growing degree days, base 60°F
1,816

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24400
February1,00202
March753137
April3877148
May13473409
June12235673
July1352815
August2303766
September67131516
October33617202
November713032
December1,08002

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 9.1 km from Nauvoo. 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 USC00133007 (Ft Madison). Public domain.