Leavenworth County climate

Leavenworth County Frost Dates and Growing Season

NOAA 1991-2020 normals for Leavenworth 3SW, 12.2 km from Leavenworth County, elevation 871 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Leavenworth 3SW. 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 19 and the first fall freeze around October 19, a growing season of about 181 days.

Median at 36°F
last April 30, first October 8
Median at 32°F
last April 19, first October 19
Median at 28°F
last April 9, 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 13May 8May 6May 3Apr 30Apr 28Apr 25Apr 20Apr 16
32°FMay 4Apr 30Apr 26Apr 23Apr 19Apr 16Apr 13Apr 10Apr 5
28°FApr 23Apr 18Apr 14Apr 11Apr 9Apr 6Apr 3Mar 31Mar 25
24°FApr 14Apr 9Apr 5Apr 1Mar 30Mar 25Mar 21Mar 17Mar 12
20°FApr 4Mar 31Mar 25Mar 22Mar 18Mar 15Mar 11Mar 6Feb 28
16°FMar 26Mar 19Mar 15Mar 12Mar 9Mar 5Mar 2Feb 26Feb 20

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 29Oct 3Oct 5Oct 8Oct 12Oct 14Oct 17Oct 22
32°FOct 2Oct 9Oct 13Oct 16Oct 19Oct 21Oct 23Oct 26Oct 30
28°FOct 15Oct 19Oct 23Oct 25Oct 27Oct 30Nov 1Nov 4Nov 9
24°FOct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 15Nov 21
20°FNov 1Nov 4Nov 8Nov 11Nov 14Nov 17Nov 22Nov 27Dec 3
16°FNov 8Nov 13Nov 17Nov 21Nov 25Nov 28Dec 1Dec 6Dec 12

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°F179173168164160157154150143
32°F200193188185181177173168160
28°F220213208204200196193188182
24°F243235230225220216211207199
20°F265257251246241237232226216
16°F284276271266260256249244236

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
5,507
Cooling degree days, base 65°F
1,134
Growing degree days, base 40°F
5,989
Growing degree days, base 45°F
4,754
Growing degree days, base 50°F
3,647
Growing degree days, base 55°F
2,679
Growing degree days, base 60°F
1,841

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18800
February93906
March711248
April3759162
May13565406
June10235675
July1364827
August2313776
September71126506
October33219210
November697131
December1,04601

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 12.2 km from Leavenworth 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 USC00144589 (Leavenworth 3SW). Public domain.