Landen climate

Landen Frost Dates and Growing Season

NOAA 1991-2020 normals for Hamilton Butler CO Rgnl AP, 21.6 km from Landen, elevation 634 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hamilton Butler CO Rgnl 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 22 and the first fall freeze around October 18, a growing season of about 178 days.

Median at 36°F
last May 2, first October 7
Median at 32°F
last April 22, first October 18
Median at 28°F
last April 8, first October 27

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 19May 13May 8May 6May 2Apr 30Apr 26Apr 22Apr 18
32°FMay 10May 4Apr 29Apr 25Apr 22Apr 18Apr 15Apr 11Apr 6
28°FApr 28Apr 20Apr 16Apr 12Apr 8Apr 6Apr 3Mar 31Mar 26
24°FApr 11Apr 4Apr 2Mar 31Mar 29Mar 26Mar 22Mar 18Mar 12
20°FMar 31Mar 27Mar 24Mar 20Mar 17Mar 14Mar 10Mar 6Feb 28
16°FMar 22Mar 18Mar 14Mar 10Mar 7Mar 3Feb 28Feb 23Feb 15

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 25Sep 30Oct 2Oct 5Oct 7Oct 9Oct 12Oct 15Oct 20
32°FOct 5Oct 9Oct 12Oct 15Oct 18Oct 20Oct 23Oct 25Oct 29
28°FOct 15Oct 20Oct 23Oct 25Oct 27Oct 29Nov 1Nov 3Nov 8
24°FOct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 15Nov 21
20°FNov 2Nov 6Nov 10Nov 13Nov 17Nov 21Nov 26Dec 1Dec 6
16°FNov 9Nov 15Nov 20Nov 26Dec 1Dec 3Dec 7Dec 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°F177170166163159154150146138
32°F198191186182178174170165157
28°F221213208204200196191186178
24°F243237232227223219215210203
20°F269261255249245241236232225
16°F298287281275270264257251243

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
5,111
Cooling degree days, base 65°F
1,067
Growing degree days, base 40°F
6,047
Growing degree days, base 45°F
4,769
Growing degree days, base 50°F
3,637
Growing degree days, base 55°F
2,640
Growing degree days, base 60°F
1,781

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,06307
February881011
March689357
April34114187
May12682426
June14219655
July1328792
August3286749
September66117502
October33317197
November655143
December941011

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 21.6 km from Landen. 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 USW00053855 (Hamilton Butler CO Rgnl AP). Public domain.