Danforth climate

Danforth Frost Dates and Growing Season

NOAA 1991-2020 normals for Danforth, 0.5 km from Danforth, elevation 475 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Danforth. 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 25 and the first fall freeze around September 24, a growing season of about 119 days.

Median at 36°F
last June 5, first September 11
Median at 32°F
last May 25, first September 24
Median at 28°F
last May 11, first October 3

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 20Jun 15Jun 11Jun 7Jun 5Jun 2May 30May 28May 24
32°FJun 8Jun 3May 31May 28May 25May 22May 19May 15May 10
28°FMay 27May 22May 18May 14May 11May 7May 4May 1Apr 27
24°FMay 12May 6May 2Apr 30Apr 27Apr 24Apr 22Apr 17Apr 12
20°FApr 28Apr 23Apr 20Apr 17Apr 13Apr 10Apr 8Apr 5Apr 3
16°FApr 18Apr 12Apr 9Apr 7Apr 5Apr 3Apr 1Mar 30Mar 25

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 29Sep 2Sep 5Sep 8Sep 11Sep 13Sep 17Sep 21Sep 26
32°FSep 8Sep 13Sep 17Sep 21Sep 24Sep 26Sep 30Oct 2Oct 5
28°FSep 22Sep 26Sep 30Oct 1Oct 3Oct 6Oct 9Oct 12Oct 18
24°FOct 2Oct 6Oct 9Oct 11Oct 14Oct 18Oct 22Oct 26Nov 1
20°FOct 13Oct 18Oct 23Oct 26Oct 30Nov 1Nov 4Nov 8Nov 14
16°FOct 29Nov 2Nov 5Nov 9Nov 12Nov 15Nov 19Nov 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°F1171101051009693898475
32°F13813212712311911511010698
28°F162156151147143139135130123
24°F189182176172168164161155149
20°F218211206202197193189183176
16°F240234229224221217213209200

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
8,950
Cooling degree days, base 65°F
206
Growing degree days, base 40°F
3,315
Growing degree days, base 45°F
2,411
Growing degree days, base 50°F
1,649
Growing degree days, base 55°F
1,012
Growing degree days, base 60°F
523

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,59900
February1,41000
March1,21700
April78307
May4454109
June16138333
July5983490
August7865453
September27415220
October639035
November93504
December1,35100

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 0.5 km from Danforth. 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 USC00171833 (Danforth). Public domain.