Troy climate

Troy Frost Dates and Growing Season

NOAA 1991-2020 normals for Troy, 2.3 km from Troy, elevation 1929 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Troy. 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 14 and the first fall freeze around September 25, a growing season of about 132 days.

Median at 36°F
last June 2, first September 7
Median at 32°F
last May 14, first September 25
Median at 28°F
last April 29, first October 6

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°FJun 27Jun 15Jun 9Jun 5Jun 2May 30May 27May 23May 18
32°FMay 31May 25May 21May 17May 14May 11May 8May 4Apr 29
28°FMay 14May 8May 4May 1Apr 29Apr 27Apr 24Apr 19Apr 14
24°FApr 29Apr 22Apr 17Apr 12Apr 8Apr 5Apr 1Mar 28Mar 19
20°FApr 9Apr 3Mar 30Mar 25Mar 20Mar 15Mar 10Mar 6Feb 28
16°FMar 23Mar 15Mar 11Mar 7Mar 4Mar 1Feb 25Feb 20Feb 11

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°FAug 24Aug 31Sep 2Sep 5Sep 7Sep 10Sep 14Sep 19Sep 24
32°FSep 9Sep 14Sep 18Sep 22Sep 25Sep 27Oct 1Oct 4Oct 9
28°FSep 21Sep 28Oct 1Oct 3Oct 6Oct 11Oct 16Oct 21Oct 30
24°FOct 1Oct 8Oct 14Oct 19Oct 24Oct 29Nov 3Nov 8Nov 16
20°FOct 13Oct 21Oct 28Nov 2Nov 8Nov 12Nov 19Nov 25Dec 2
16°FOct 25Nov 2Nov 10Nov 16Nov 22Nov 27Dec 2Dec 10Dec 22

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°F1191101051009691857970
32°F155147141136132128122116108
28°F190180172167162157152148140
24°F229219211204198192186177167
20°F265253245239233227219210200
16°F296284274267261254247239229

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
6,898
Cooling degree days, base 65°F
288
Growing degree days, base 40°F
3,830
Growing degree days, base 45°F
2,795
Growing degree days, base 50°F
1,931
Growing degree days, base 55°F
1,216
Growing degree days, base 60°F
662

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,15300
February94400
March81103
April569034
May3175181
June15232332
July34129560
August49107522
September21716261
October603039
November90201
December1,14900

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 2.3 km from Troy. 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 USC00248390 (Troy). Public domain.