Rooks County climate

Rooks County Frost Dates and Growing Season

NOAA 1991-2020 normals for Plainville 4WNW, 12.6 km from Rooks County, elevation 2194 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Plainville 4WNW. 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 23 and the first fall freeze around October 20, a growing season of about 178 days.

Median at 36°F
last May 3, first October 10
Median at 32°F
last April 23, first October 20
Median at 28°F
last April 12, first October 29

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 14May 10May 7May 5May 3Apr 30Apr 28Apr 24Apr 19
32°FMay 6May 2Apr 30Apr 26Apr 23Apr 19Apr 16Apr 12Apr 7
28°FApr 30Apr 24Apr 20Apr 16Apr 12Apr 9Apr 5Apr 2Mar 27
24°FApr 19Apr 13Apr 9Apr 6Apr 3Mar 31Mar 26Mar 20Mar 13
20°FApr 11Apr 6Apr 2Mar 29Mar 23Mar 18Mar 13Mar 8Mar 3
16°FApr 5Mar 31Mar 23Mar 17Mar 12Mar 8Mar 4Mar 1Feb 22

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 27Oct 1Oct 4Oct 7Oct 10Oct 13Oct 15Oct 19Oct 23
32°FOct 3Oct 10Oct 14Oct 17Oct 20Oct 22Oct 24Oct 27Nov 1
28°FOct 13Oct 19Oct 23Oct 26Oct 29Oct 31Nov 2Nov 5Nov 12
24°FOct 21Oct 28Oct 31Nov 2Nov 5Nov 8Nov 12Nov 16Nov 23
20°FOct 30Nov 3Nov 7Nov 11Nov 15Nov 19Nov 23Nov 28Dec 2
16°FNov 4Nov 11Nov 16Nov 21Nov 24Nov 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°F178171167163160156152148142
32°F198191186182178174170165158
28°F219211206201197192188183176
24°F240233226221216212207201193
20°F262253247241235231225219210
16°F284274267261256250244237227

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
5,487
Cooling degree days, base 65°F
1,277
Growing degree days, base 40°F
6,087
Growing degree days, base 45°F
4,844
Growing degree days, base 50°F
3,749
Growing degree days, base 55°F
2,790
Growing degree days, base 60°F
1,966

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,10701
February91507
March703147
April4138141
May16970377
June17254687
July2412876
August4351812
September71159542
October33721217
November702139
December1,04602

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 12.6 km from Rooks 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 USC00146435 (Plainville 4WNW). Public domain.