Atkins climate

Atkins Frost Dates and Growing Season

NOAA 1991-2020 normals for Cedar Rapids Muni AP, 17.4 km from Atkins, elevation 868 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cedar Rapids Muni 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 27 and the first fall freeze around October 11, a growing season of about 165 days.

Median at 36°F
last May 6, first October 1
Median at 32°F
last April 27, first October 11
Median at 28°F
last April 16, first October 21

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 20May 14May 11May 8May 6May 3May 1Apr 28Apr 23
32°FMay 11May 6May 3Apr 30Apr 27Apr 24Apr 22Apr 17Apr 13
28°FMay 1Apr 26Apr 22Apr 20Apr 16Apr 13Apr 10Apr 7Apr 3
24°FApr 21Apr 16Apr 12Apr 9Apr 6Apr 4Apr 1Mar 30Mar 23
20°FApr 11Apr 6Apr 3Apr 1Mar 30Mar 26Mar 21Mar 18Mar 11
16°FApr 2Mar 29Mar 25Mar 21Mar 18Mar 14Mar 12Mar 7Mar 3

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 16Sep 21Sep 24Sep 28Oct 1Oct 3Oct 6Oct 9Oct 14
32°FSep 25Oct 1Oct 5Oct 8Oct 11Oct 13Oct 16Oct 19Oct 23
28°FOct 7Oct 12Oct 16Oct 19Oct 21Oct 23Oct 26Oct 29Nov 1
24°FOct 17Oct 22Oct 24Oct 27Oct 29Nov 1Nov 3Nov 6Nov 12
20°FOct 27Oct 31Nov 2Nov 5Nov 8Nov 10Nov 13Nov 18Nov 24
16°FNov 3Nov 7Nov 10Nov 13Nov 16Nov 20Nov 24Nov 28Dec 3

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°F165159154150147143139135129
32°F184177173169165162157152146
28°F207199194190186183179174166
24°F227219214209206202198192186
20°F245238234229224220215210204
16°F265258252246243238234229222

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
6,824
Cooling degree days, base 65°F
755
Growing degree days, base 40°F
5,046
Growing degree days, base 45°F
3,944
Growing degree days, base 50°F
2,962
Growing degree days, base 55°F
2,099
Growing degree days, base 60°F
1,360

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,40700
February1,14701
March883125
April490598
May19752333
June26173597
July5245705
August13193645
September12877405
October45310135
November842018
December1,23401

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 17.4 km from Atkins. 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 USW00014990 (Cedar Rapids Muni AP). Public domain.