Milroy climate

Milroy Frost Dates and Growing Season

NOAA 1991-2020 normals for Rushville, 12 km from Milroy, elevation 948 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rushville. 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 23, a growing season of about 185 days.

Median at 36°F
last April 30, first October 13
Median at 32°F
last April 19, first October 23
Median at 28°F
last April 6, first November 1

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 15May 9May 6May 2Apr 30Apr 27Apr 24Apr 20Apr 16
32°FMay 5Apr 30Apr 26Apr 22Apr 19Apr 16Apr 13Apr 10Apr 4
28°FApr 23Apr 17Apr 14Apr 10Apr 6Apr 3Apr 1Mar 29Mar 23
24°FApr 10Apr 4Apr 1Mar 31Mar 27Mar 24Mar 20Mar 16Mar 11
20°FApr 2Mar 28Mar 22Mar 20Mar 16Mar 13Mar 10Mar 5Feb 28
16°FMar 22Mar 18Mar 14Mar 11Mar 7Mar 3Feb 28Feb 22Feb 13

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 29Oct 5Oct 8Oct 10Oct 13Oct 15Oct 17Oct 20Oct 24
32°FOct 11Oct 15Oct 18Oct 20Oct 23Oct 25Oct 27Oct 30Nov 2
28°FOct 21Oct 24Oct 28Oct 30Nov 1Nov 3Nov 6Nov 10Nov 14
24°FNov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 18Nov 22Nov 29
20°FNov 7Nov 12Nov 16Nov 20Nov 25Nov 29Dec 2Dec 7Dec 16
16°FNov 16Nov 22Nov 28Dec 1Dec 5Dec 9Dec 14Dec 21Dec 27

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°F182176172167163160156151145
32°F203197192189185182178172164
28°F227220215211206203199195187
24°F252244239234230226221215209
20°F278269263259253248243237228
16°F300291285279274269264258251

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
5,683
Cooling degree days, base 65°F
881
Growing degree days, base 40°F
5,592
Growing degree days, base 45°F
4,382
Growing degree days, base 50°F
3,306
Growing degree days, base 55°F
2,360
Growing degree days, base 60°F
1,550

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18602
February96504
March772140
April4138144
May15871387
June21193623
July3266729
August7224682
September85102469
October36016185
November701136
December1,01406

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 km from Milroy. 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 USC00127646 (Rushville). Public domain.