Lamoni climate

Lamoni Frost Dates and Growing Season

NOAA 1991-2020 normals for Lamoni, 0 km from Lamoni, elevation 1128 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lamoni. 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 17 and the first fall freeze around October 21, a growing season of about 184 days.

Median at 36°F
last April 29, first October 10
Median at 32°F
last April 17, first October 21
Median at 28°F
last April 8, first October 30

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 10May 6May 3May 1Apr 29Apr 25Apr 22Apr 18Apr 14
32°FMay 1Apr 27Apr 23Apr 20Apr 17Apr 14Apr 12Apr 8Apr 4
28°FApr 23Apr 18Apr 14Apr 11Apr 8Apr 5Apr 2Mar 31Mar 24
24°FApr 13Apr 9Apr 5Apr 2Mar 31Mar 28Mar 23Mar 19Mar 12
20°FApr 5Mar 31Mar 28Mar 24Mar 20Mar 17Mar 13Mar 8Mar 3
16°FMar 28Mar 22Mar 18Mar 14Mar 10Mar 7Mar 4Mar 1Feb 25

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 26Sep 30Oct 4Oct 7Oct 10Oct 13Oct 17Oct 20Oct 25
32°FOct 6Oct 11Oct 14Oct 18Oct 21Oct 24Oct 26Oct 29Nov 2
28°FOct 16Oct 22Oct 25Oct 28Oct 30Nov 1Nov 4Nov 7Nov 13
24°FOct 27Nov 1Nov 2Nov 5Nov 8Nov 11Nov 14Nov 17Nov 23
20°FNov 3Nov 7Nov 10Nov 13Nov 15Nov 18Nov 22Nov 27Dec 3
16°FNov 10Nov 14Nov 17Nov 21Nov 25Nov 28Dec 1Dec 6Dec 13

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°F183178174170166162157153147
32°F204198192188184181177172165
28°F224217211208204200196191185
24°F244236231226222218215210202
20°F263256250245241237232225218
16°F281274268264259254249243235

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
6,012
Cooling degree days, base 65°F
1,145
Growing degree days, base 40°F
5,820
Growing degree days, base 45°F
4,638
Growing degree days, base 50°F
3,581
Growing degree days, base 55°F
2,646
Growing degree days, base 60°F
1,830

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28600
February1,03903
March783241
April4208140
May15274396
June14242678
July1364828
August4309770
September81129500
October36518193
November749031
December1,11902

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 km from Lamoni. 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 USC00134585 (Lamoni). Public domain.