Warsaw climate

Warsaw Frost Dates and Growing Season

NOAA 1991-2020 normals for Glencoe 6 Nw, 0.7 km from Warsaw, elevation 490 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Glencoe 6 Nw. 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 23 and the first fall freeze around October 21, a growing season of about 179 days.

Median at 36°F
last May 3, first October 11
Median at 32°F
last April 23, first October 21
Median at 28°F
last April 11, first October 31

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 18May 13May 9May 6May 3May 1Apr 28Apr 23Apr 19
32°FMay 9May 4Apr 30Apr 26Apr 23Apr 20Apr 17Apr 14Apr 9
28°FApr 30Apr 22Apr 17Apr 14Apr 11Apr 8Apr 5Apr 3Mar 29
24°FApr 15Apr 9Apr 6Apr 3Apr 1Mar 29Mar 27Mar 23Mar 17
20°FApr 4Mar 31Mar 28Mar 25Mar 22Mar 18Mar 15Mar 11Mar 5
16°FMar 27Mar 22Mar 18Mar 15Mar 11Mar 8Mar 5Feb 28Feb 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°FSep 29Oct 4Oct 6Oct 9Oct 11Oct 13Oct 16Oct 18Oct 22
32°FOct 7Oct 13Oct 16Oct 19Oct 21Oct 23Oct 25Oct 28Oct 31
28°FOct 18Oct 22Oct 26Oct 28Oct 31Nov 1Nov 3Nov 6Nov 11
24°FOct 29Nov 1Nov 3Nov 6Nov 9Nov 11Nov 14Nov 18Nov 24
20°FNov 5Nov 9Nov 13Nov 16Nov 19Nov 23Nov 27Dec 1Dec 6
16°FNov 13Nov 18Nov 23Nov 27Dec 1Dec 3Dec 8Dec 15Dec 22

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°F178173168164161157154149142
32°F199193187183179175171167160
28°F220214209205202197192187180
24°F243236231227222218214209202
20°F269260254249244239235229223
16°F291283275270266261255249240

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
5,261
Cooling degree days, base 65°F
925
Growing degree days, base 40°F
5,828
Growing degree days, base 45°F
4,555
Growing degree days, base 50°F
3,433
Growing degree days, base 55°F
2,465
Growing degree days, base 60°F
1,631

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11203
February91505
March718039
April36514175
May13569407
June11178618
July1287751
August3248709
September69109491
October33320195
November651134
December95005

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 0.7 km from Warsaw. 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 USC00153250 (Glencoe 6 Nw). Public domain.