Pekin climate

Pekin Frost Dates and Growing Season

NOAA 1991-2020 normals for Peoria Gtr Peoria AP, 11.6 km from Pekin, elevation 650 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Peoria Gtr Peoria 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 16 and the first fall freeze around October 23, a growing season of about 189 days.

Median at 36°F
last April 27, first October 14
Median at 32°F
last April 16, first October 23
Median at 28°F
last April 5, first November 2

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 14May 8May 4Apr 30Apr 27Apr 24Apr 21Apr 18Apr 14
32°FMay 4Apr 28Apr 23Apr 20Apr 16Apr 13Apr 10Apr 6Apr 2
28°FApr 21Apr 15Apr 11Apr 7Apr 5Apr 2Mar 31Mar 26Mar 19
24°FApr 10Apr 5Apr 1Mar 29Mar 26Mar 21Mar 17Mar 13Mar 8
20°FMar 31Mar 26Mar 21Mar 18Mar 15Mar 11Mar 8Mar 4Feb 28
16°FMar 23Mar 17Mar 14Mar 10Mar 7Mar 4Feb 28Feb 25Feb 17

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 28Oct 4Oct 8Oct 11Oct 14Oct 16Oct 19Oct 22Oct 25
32°FOct 9Oct 15Oct 18Oct 20Oct 23Oct 25Oct 28Oct 31Nov 3
28°FOct 21Oct 26Oct 29Oct 31Nov 2Nov 4Nov 7Nov 11Nov 16
24°FNov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 19Nov 23Nov 28
20°FNov 8Nov 12Nov 16Nov 19Nov 23Nov 26Nov 30Dec 3Dec 8
16°FNov 14Nov 20Nov 25Nov 29Dec 2Dec 5Dec 9Dec 13Dec 18

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°F187181175171168164160154147
32°F209202198193189185180175167
28°F232225220216212208204199192
24°F255247242237233229225221214
20°F274266261256252247243237230
16°F292284279274270265260254245

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
5,614
Cooling degree days, base 65°F
1,157
Growing degree days, base 40°F
5,978
Growing degree days, base 45°F
4,760
Growing degree days, base 50°F
3,670
Growing degree days, base 55°F
2,704
Growing degree days, base 60°F
1,865

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22101
February97805
March734245
April37613163
May13588423
June13247684
July1351815
August3297759
September67137523
October33522209
November694140
December1,05904

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 11.6 km from Pekin. 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 USW00014842 (Peoria Gtr Peoria AP). Public domain.