Osceola County climate

Osceola County Frost Dates and Growing Season

NOAA 1991-2020 normals for Sibley, 10.4 km from Osceola County, elevation 1529 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sibley. 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 May 5 and the first fall freeze around October 3, a growing season of about 152 days.

Median at 36°F
last May 12, first September 27
Median at 32°F
last May 5, first October 3
Median at 28°F
last April 25, first October 13

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 25May 20May 16May 14May 12May 9May 7May 5May 1
32°FMay 17May 13May 9May 6May 5May 2Apr 30Apr 27Apr 22
28°FMay 8May 4May 1Apr 29Apr 25Apr 22Apr 19Apr 15Apr 11
24°FMay 1Apr 25Apr 21Apr 18Apr 15Apr 12Apr 9Apr 6Apr 3
20°FApr 22Apr 17Apr 12Apr 9Apr 7Apr 4Apr 2Mar 29Mar 21
16°FApr 14Apr 9Apr 5Apr 3Mar 31Mar 28Mar 23Mar 19Mar 12

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 11Sep 17Sep 21Sep 24Sep 27Sep 29Oct 1Oct 4Oct 8
32°FSep 21Sep 25Sep 28Oct 1Oct 3Oct 6Oct 9Oct 12Oct 17
28°FSep 29Oct 2Oct 6Oct 10Oct 13Oct 16Oct 19Oct 22Oct 27
24°FOct 7Oct 14Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 6
20°FOct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 6Nov 10Nov 15
16°FOct 28Nov 1Nov 4Nov 6Nov 9Nov 11Nov 14Nov 18Nov 23

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°F153147143140136133129124118
32°F171164160156152148144139133
28°F189183178174171167162156150
24°F210203197193189185181176170
20°F230221216211207203199194187
16°F245238233228224220214210202

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
8,036
Cooling degree days, base 65°F
592
Growing degree days, base 40°F
4,474
Growing degree days, base 45°F
3,467
Growing degree days, base 50°F
2,569
Growing degree days, base 55°F
1,787
Growing degree days, base 60°F
1,123

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,58400
February1,30500
March1,06008
April623259
May27834260
June52136535
July15207657
August27148586
September16659357
October540698
November977010
December1,41000

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 10.4 km from Osceola County. 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 USC00137664 (Sibley). Public domain.