Franklin County climate

Franklin County Frost Dates and Growing Season

NOAA 1991-2020 normals for Rangeley, 15.6 km from Franklin County, elevation 1530 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rangeley. 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 23 and the first fall freeze around September 27, a growing season of about 127 days.

Median at 36°F
last June 3, first September 15
Median at 32°F
last May 23, first September 27
Median at 28°F
last May 10, first October 7

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 15Jun 11Jun 8Jun 5Jun 3Jun 1May 30May 27May 23
32°FJun 3May 31May 29May 26May 23May 20May 17May 14May 10
28°FMay 22May 18May 15May 13May 10May 8May 5May 2Apr 29
24°FMay 11May 6May 4May 2Apr 30Apr 28Apr 25Apr 23Apr 18
20°FApr 30Apr 27Apr 24Apr 22Apr 20Apr 17Apr 15Apr 11Apr 8
16°FApr 23Apr 19Apr 16Apr 14Apr 11Apr 9Apr 7Apr 5Apr 3

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 2Sep 6Sep 10Sep 12Sep 15Sep 18Sep 21Sep 24Sep 28
32°FSep 14Sep 19Sep 22Sep 25Sep 27Oct 1Oct 2Oct 5Oct 9
28°FSep 26Sep 30Oct 2Oct 4Oct 7Oct 9Oct 12Oct 16Oct 22
24°FOct 5Oct 9Oct 13Oct 17Oct 20Oct 23Oct 27Oct 31Nov 4
20°FOct 18Oct 25Oct 28Oct 31Nov 2Nov 4Nov 7Nov 11Nov 16
16°FNov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 18Nov 22Nov 26

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°F123116111107104101969286
32°F146139135131127124120116110
28°F169162158153150146142138132
24°F192186182178174170165161154
20°F213206202198195192189184177
16°F232226221217214211207203197

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
9,466
Cooling degree days, base 65°F
136
Growing degree days, base 40°F
3,099
Growing degree days, base 45°F
2,230
Growing degree days, base 50°F
1,483
Growing degree days, base 55°F
870
Growing degree days, base 60°F
410

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,65200
February1,45200
March1,31600
April86006
May476394
June18824292
July7258451
August10038403
September28812203
October668031
November99502
December1,40000

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 15.6 km from Franklin 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 USC00177037 (Rangeley). Public domain.