Franklin County climate

Franklin County Frost Dates and Growing Season

NOAA 1991-2020 normals for Enosburg Falls, 10 km from Franklin County, elevation 420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Enosburg Falls. 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 October 1, a growing season of about 139 days.

Median at 36°F
last May 28, first September 19
Median at 32°F
last May 14, first October 1
Median at 28°F
last May 3, first October 13

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 9Jun 5Jun 2May 30May 28May 25May 21May 17May 12
32°FMay 28May 24May 20May 17May 14May 11May 8May 4Apr 30
28°FMay 17May 11May 8May 5May 3Apr 30Apr 28Apr 25Apr 20
24°FMay 5May 1Apr 27Apr 25Apr 22Apr 20Apr 18Apr 14Apr 8
20°FApr 23Apr 20Apr 17Apr 13Apr 10Apr 7Apr 5Apr 3Mar 31
16°FApr 16Apr 11Apr 7Apr 5Apr 3Apr 1Mar 31Mar 27Mar 22

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 6Sep 10Sep 14Sep 16Sep 19Sep 21Sep 24Sep 27Oct 2
32°FSep 18Sep 23Sep 26Sep 29Oct 1Oct 4Oct 6Oct 10Oct 17
28°FSep 29Oct 3Oct 6Oct 9Oct 13Oct 16Oct 20Oct 25Oct 30
24°FOct 9Oct 15Oct 19Oct 23Oct 26Oct 29Nov 1Nov 4Nov 9
20°FOct 23Oct 29Nov 1Nov 3Nov 6Nov 8Nov 11Nov 14Nov 20
16°FNov 3Nov 7Nov 11Nov 13Nov 16Nov 19Nov 22Nov 26Nov 30

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°F13312712211811411010610295
32°F158152147143139134130125118
28°F184176171167164158154149142
24°F206200194190187182178173165
20°F226221216212209204201196189
16°F244238233229226222218214207

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
7,504
Cooling degree days, base 65°F
433
Growing degree days, base 40°F
4,283
Growing degree days, base 45°F
3,244
Growing degree days, base 50°F
2,335
Growing degree days, base 55°F
1,549
Growing degree days, base 60°F
906

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,43501
February1,24200
March1,07006
April626249
May28422231
June8281449
July18159606
August36126555
September17541325
October492398
November827014
December1,21801

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 10 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 USC00432769 (Enosburg Falls). Public domain.