Oquawka climate

Oquawka Frost Dates and Growing Season

NOAA 1991-2020 normals for Gladstone Dam 18, 8.5 km from Oquawka, elevation 538 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Gladstone Dam 18. 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 29, a growing season of about 202 days.

Median at 36°F
last April 20, first October 19
Median at 32°F
last April 8, first October 29
Median at 28°F
last March 31, first November 7

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 22Apr 20Apr 17Apr 14Apr 10Apr 6
32°FApr 23Apr 18Apr 14Apr 11Apr 8Apr 6Apr 3Apr 1Mar 26
28°FApr 13Apr 8Apr 5Apr 2Mar 31Mar 29Mar 24Mar 20Mar 14
24°FApr 5Apr 1Mar 29Mar 25Mar 20Mar 18Mar 14Mar 10Mar 5
20°FMar 29Mar 24Mar 19Mar 15Mar 12Mar 9Mar 6Mar 3Feb 27
16°FMar 20Mar 15Mar 11Mar 8Mar 5Mar 3Feb 28Feb 25Feb 18

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 10Oct 14Oct 17Oct 19Oct 22Oct 24Oct 27Oct 31
32°FOct 17Oct 21Oct 25Oct 27Oct 29Oct 31Nov 2Nov 5Nov 10
28°FOct 27Oct 31Nov 2Nov 4Nov 7Nov 9Nov 12Nov 16Nov 21
24°FNov 4Nov 8Nov 11Nov 14Nov 17Nov 20Nov 23Nov 27Dec 2
20°FNov 9Nov 15Nov 19Nov 22Nov 26Nov 29Dec 2Dec 7Dec 13
16°FNov 18Nov 23Nov 27Dec 1Dec 3Dec 7Dec 11Dec 16Dec 21

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°F199193189185181177173168161
32°F220214209206202199195190182
28°F242234229225222218214210203
24°F263255249244240237232227222
20°F279272266261257253249243236
16°F295289283278273269264258251

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
5,853
Cooling degree days, base 65°F
1,108
Growing degree days, base 40°F
5,842
Growing degree days, base 45°F
4,648
Growing degree days, base 50°F
3,578
Growing degree days, base 55°F
2,626
Growing degree days, base 60°F
1,800

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26900
February1,02903
March788235
April3979149
May13872404
June15242678
July1348812
August3291753
September70127508
October33817200
November714034
December1,09302

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 8.5 km from Oquawka. 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 USC00113455 (Gladstone Dam 18). Public domain.