Waukon climate

Waukon Frost Dates and Growing Season

NOAA 1991-2020 normals for Waukon, 0.7 km from Waukon, elevation 1275 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Waukon. 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 May 2 and the first fall freeze around October 11, a growing season of about 161 days.

Median at 36°F
last May 12, first October 1
Median at 32°F
last May 2, first October 11
Median at 28°F
last April 21, first October 22

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 26May 22May 18May 14May 12May 9May 5May 2Apr 29
32°FMay 16May 11May 7May 4May 2Apr 30Apr 26Apr 22Apr 17
28°FMay 6May 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 11Apr 6
24°FApr 26Apr 21Apr 16Apr 12Apr 9Apr 6Apr 4Apr 1Mar 27
20°FApr 16Apr 9Apr 5Apr 3Apr 1Mar 30Mar 26Mar 21Mar 16
16°FApr 4Apr 1Mar 30Mar 26Mar 23Mar 19Mar 16Mar 13Mar 9

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 19Sep 23Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 14
32°FSep 28Oct 1Oct 4Oct 8Oct 11Oct 13Oct 17Oct 20Oct 24
28°FOct 7Oct 12Oct 16Oct 19Oct 22Oct 24Oct 27Oct 30Nov 3
24°FOct 20Oct 24Oct 27Oct 30Nov 1Nov 3Nov 6Nov 10Nov 15
20°FOct 29Nov 2Nov 5Nov 8Nov 10Nov 12Nov 15Nov 19Nov 24
16°FNov 5Nov 10Nov 13Nov 15Nov 19Nov 21Nov 25Nov 28Dec 2

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°F160153149144141137133129122
32°F179173169165161157152147142
28°F202195190186182178174169162
24°F225217212208205200196190182
20°F245237231227223220216212206
16°F263255250246241237233228222

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
7,658
Cooling degree days, base 65°F
570
Growing degree days, base 40°F
4,480
Growing degree days, base 45°F
3,457
Growing degree days, base 50°F
2,549
Growing degree days, base 55°F
1,759
Growing degree days, base 60°F
1,095

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51300
February1,24600
March1,018013
April601154
May28625236
June51126525
July11211665
August23152594
September15548352
October5127103
November91508
December1,32700

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 Waukon. 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 USC00138755 (Waukon). Public domain.