Olathe climate

Olathe Frost Dates and Growing Season

NOAA 1991-2020 normals for Montrose #2, 16 km from Olathe, elevation 5789 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Montrose #2. 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 28 and the first fall freeze around October 14, a growing season of about 167 days.

Median at 36°F
last May 11, first October 3
Median at 32°F
last April 28, first October 14
Median at 28°F
last April 14, first October 24

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 23May 19May 17May 14May 11May 8May 5May 2Apr 28
32°FMay 12May 7May 3Apr 30Apr 28Apr 25Apr 22Apr 18Apr 13
28°FApr 30Apr 25Apr 20Apr 17Apr 14Apr 10Apr 7Apr 3Mar 29
24°FApr 18Apr 11Apr 7Apr 3Mar 31Mar 27Mar 22Mar 17Mar 10
20°FApr 3Mar 26Mar 20Mar 16Mar 11Mar 8Mar 5Mar 1Feb 23
16°FMar 15Mar 9Mar 5Mar 2Feb 26Feb 22Feb 17Feb 13Feb 6

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 22Sep 26Sep 29Oct 1Oct 3Oct 5Oct 8Oct 12Oct 17
32°FOct 1Oct 4Oct 7Oct 11Oct 14Oct 16Oct 19Oct 23Oct 27
28°FOct 10Oct 15Oct 19Oct 21Oct 24Oct 28Nov 1Nov 3Nov 7
24°FOct 20Oct 25Oct 29Nov 1Nov 4Nov 6Nov 10Nov 13Nov 18
20°FOct 29Nov 4Nov 7Nov 11Nov 14Nov 17Nov 19Nov 22Nov 26
16°FNov 7Nov 13Nov 16Nov 20Nov 23Nov 25Nov 28Dec 1Dec 6

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°F162157153149145142137133127
32°F186179175171167163159155148
28°F212205200195191186182177171
24°F239233227222217212206200191
20°F269261255249245239235228218
16°F292285280275270265260253244

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
5,681
Cooling degree days, base 65°F
793
Growing degree days, base 40°F
5,292
Growing degree days, base 45°F
4,091
Growing degree days, base 50°F
3,044
Growing degree days, base 55°F
2,155
Growing degree days, base 60°F
1,404

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12100
February84801
March667022
April4412103
May20028309
June33164582
July1302766
August4230691
September8965430
October4071129
November759012
December1,11100

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 16 km from Olathe. 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 USC00055722 (Montrose #2). Public domain.