Rush County climate

Rush County Frost Dates and Growing Season

NOAA 1991-2020 normals for Bison 3NW, 7.9 km from Rush County, elevation 2040 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bison 3NW. 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 30 and the first fall freeze around October 10, a growing season of about 162 days.

Median at 36°F
last May 8, first October 1
Median at 32°F
last April 30, first October 10
Median at 28°F
last April 21, first October 19

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 21May 16May 13May 11May 8May 6May 2Apr 30Apr 26
32°FMay 11May 7May 4May 1Apr 30Apr 27Apr 24Apr 21Apr 16
28°FMay 3Apr 29Apr 26Apr 24Apr 21Apr 18Apr 14Apr 11Apr 5
24°FApr 25Apr 20Apr 17Apr 14Apr 11Apr 7Apr 4Apr 1Mar 25
20°FApr 18Apr 12Apr 8Apr 4Apr 1Mar 29Mar 25Mar 19Mar 12
16°FApr 10Apr 3Mar 29Mar 24Mar 20Mar 15Mar 10Mar 6Mar 1

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 19Sep 23Sep 26Sep 29Oct 1Oct 4Oct 6Oct 10Oct 14
32°FSep 26Sep 30Oct 3Oct 7Oct 10Oct 13Oct 15Oct 18Oct 21
28°FOct 4Oct 10Oct 14Oct 17Oct 19Oct 21Oct 24Oct 27Nov 1
24°FOct 16Oct 20Oct 23Oct 26Oct 28Oct 31Nov 2Nov 6Nov 10
20°FOct 23Oct 29Oct 31Nov 3Nov 6Nov 8Nov 11Nov 15Nov 22
16°FOct 30Nov 3Nov 8Nov 11Nov 13Nov 17Nov 21Nov 26Dec 2

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°F162157153149145142138134127
32°F182174169166162159154150144
28°F201194188184180177172168161
24°F223215209205200196191187181
20°F242233228223218214209205197
16°F264256249243238233228221212

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
5,486
Cooling degree days, base 65°F
1,319
Growing degree days, base 40°F
6,122
Growing degree days, base 45°F
4,887
Growing degree days, base 50°F
3,795
Growing degree days, base 55°F
2,840
Growing degree days, base 60°F
2,015

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,10401
February91307
March697152
April41111146
May16080396
June15272708
July2413876
August5353814
September71165548
October34523212
November713135
December1,05102

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 7.9 km from Rush 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 USC00140865 (Bison 3NW). Public domain.