Georgetown climate

Georgetown Frost Dates and Growing Season

NOAA 1991-2020 normals for Danbury, 16.1 km from Georgetown, elevation 405 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Danbury. 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 20 and the first fall freeze around October 20, a growing season of about 181 days.

Median at 36°F
last May 3, first October 9
Median at 32°F
last April 20, first October 20
Median at 28°F
last April 7, 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 19May 13May 9May 6May 3Apr 30Apr 27Apr 23Apr 19
32°FMay 6May 1Apr 26Apr 22Apr 20Apr 18Apr 15Apr 12Apr 7
28°FApr 21Apr 17Apr 13Apr 9Apr 7Apr 4Apr 2Mar 31Mar 26
24°FApr 9Apr 4Apr 2Mar 31Mar 29Mar 26Mar 22Mar 17Mar 12
20°FMar 31Mar 28Mar 24Mar 20Mar 17Mar 14Mar 11Mar 7Mar 1
16°FMar 23Mar 18Mar 14Mar 11Mar 8Mar 4Mar 1Feb 25Feb 18

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 3Oct 5Oct 9Oct 11Oct 14Oct 18Oct 24
32°FOct 5Oct 10Oct 14Oct 17Oct 20Oct 23Oct 27Oct 31Nov 4
28°FOct 15Oct 22Oct 26Oct 29Nov 1Nov 4Nov 7Nov 10Nov 15
24°FOct 29Nov 2Nov 7Nov 11Nov 14Nov 17Nov 21Nov 24Dec 1
20°FNov 10Nov 16Nov 20Nov 23Nov 27Nov 30Dec 3Dec 7Dec 14
16°FNov 23Nov 29Dec 2Dec 6Dec 10Dec 14Dec 19Dec 23Dec 28

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°F176169164160156153148144136
32°F202195189185181176172166160
28°F226219214210206202198193186
24°F251243237233229225221216210
20°F277270264259254250245239232
16°F301292287281277273268262253

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
5,777
Cooling degree days, base 65°F
839
Growing degree days, base 40°F
5,329
Growing degree days, base 45°F
4,139
Growing degree days, base 50°F
3,102
Growing degree days, base 55°F
2,206
Growing degree days, base 60°F
1,449

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14701
February97001
March825012
April4597101
May18543328
June30162582
July2296759
August7236694
September9586443
October3859149
November686028
December98703

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 16.1 km from Georgetown. 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 USC00061762 (Danbury). Public domain.