Lyons Falls climate

Lyons Falls Frost Dates and Growing Season

NOAA 1991-2020 normals for Highmarket 2W, 15.3 km from Lyons Falls, elevation 1804 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Highmarket 2W. 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 22 and the first fall freeze around September 26, a growing season of about 125 days.

Median at 36°F
last June 4, first September 14
Median at 32°F
last May 22, first September 26
Median at 28°F
last May 7, first October 9

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 4Jun 1May 29May 25May 19
32°FJun 7Jun 2May 30May 26May 22May 18May 15May 10May 5
28°FMay 27May 19May 14May 10May 7May 4May 1Apr 28Apr 24
24°FMay 12May 6May 2Apr 29Apr 25Apr 23Apr 20Apr 17Apr 13
20°FApr 27Apr 22Apr 19Apr 17Apr 14Apr 11Apr 9Apr 7Apr 4
16°FApr 18Apr 14Apr 11Apr 8Apr 6Apr 4Apr 2Mar 31Mar 27

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 30Sep 4Sep 7Sep 11Sep 14Sep 16Sep 19Sep 22Sep 27
32°FSep 13Sep 18Sep 21Sep 23Sep 26Sep 29Oct 1Oct 5Oct 10
28°FSep 25Sep 29Oct 2Oct 5Oct 9Oct 13Oct 17Oct 21Oct 26
24°FOct 6Oct 13Oct 18Oct 22Oct 26Oct 29Nov 1Nov 4Nov 8
20°FOct 23Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 15Nov 19
16°FNov 2Nov 7Nov 11Nov 13Nov 16Nov 18Nov 21Nov 25Nov 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°F1191121071029995918678
32°F147139134129125120116110103
28°F176169164158154150144138130
24°F202195190186181176171165158
20°F221216211207204200196192183
16°F239234229226223219216211205

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
8,910
Cooling degree days, base 65°F
164
Growing degree days, base 40°F
3,360
Growing degree days, base 45°F
2,441
Growing degree days, base 50°F
1,649
Growing degree days, base 55°F
989
Growing degree days, base 60°F
482

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,57700
February1,36500
March1,25204
April795018
May4106145
June16327319
July5969476
August8946422
September27515217
October627148
November96902
December1,32800

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 15.3 km from Lyons Falls. 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 USC00303851 (Highmarket 2W). Public domain.