Cedar County climate

Cedar County Frost Dates and Growing Season

NOAA 1991-2020 normals for Tipton, 1 km from Cedar County, elevation 820 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tipton. 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 21 and the first fall freeze around October 15, a growing season of about 175 days.

Median at 36°F
last May 1, first October 6
Median at 32°F
last April 21, first October 15
Median at 28°F
last April 12, first October 25

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 13May 9May 6May 3May 1Apr 29Apr 26Apr 23Apr 18
32°FMay 4May 1Apr 28Apr 24Apr 21Apr 18Apr 16Apr 13Apr 8
28°FApr 27Apr 22Apr 17Apr 15Apr 12Apr 9Apr 6Apr 3Mar 29
24°FApr 18Apr 12Apr 8Apr 5Apr 2Mar 31Mar 27Mar 22Mar 15
20°FApr 6Apr 1Mar 29Mar 25Mar 22Mar 18Mar 15Mar 11Mar 6
16°FMar 29Mar 23Mar 19Mar 15Mar 13Mar 9Mar 7Mar 3Feb 28

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 21Sep 27Oct 1Oct 3Oct 6Oct 8Oct 11Oct 14Oct 19
32°FOct 1Oct 6Oct 11Oct 13Oct 15Oct 18Oct 21Oct 23Oct 28
28°FOct 13Oct 18Oct 21Oct 23Oct 25Oct 28Oct 30Nov 2Nov 7
24°FOct 24Oct 28Oct 31Nov 1Nov 4Nov 7Nov 10Nov 14Nov 19
20°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 21Nov 25Dec 1
16°FNov 7Nov 12Nov 16Nov 20Nov 23Nov 27Dec 1Dec 4Dec 10

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°F175169164160157154150145137
32°F194188184180175172168163157
28°F215208203199195192187183176
24°F238230224220215210207202196
20°F258251245240237232228222215
16°F277269263257253249245240233

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
6,573
Cooling degree days, base 65°F
882
Growing degree days, base 40°F
5,295
Growing degree days, base 45°F
4,170
Growing degree days, base 50°F
3,168
Growing degree days, base 55°F
2,284
Growing degree days, base 60°F
1,518

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,38600
February1,13001
March862121
April4759108
May18063360
June23210637
July2275738
August9213670
September10197449
October40914159
November795023
December1,20102

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 1 km from Cedar County. 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 USC00138266 (Tipton). Public domain.