Lebanon climate

Lebanon Frost Dates and Growing Season

NOAA 1991-2020 normals for Lebanon, 0.6 km from Lebanon, elevation 330 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lebanon. 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 March 14 and the first fall freeze around November 18, a growing season of about 248 days.

Median at 36°F
last April 15, first October 28
Median at 32°F
last March 14, first November 18
Median at 28°F
last February 15, first December 10

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 4Apr 29Apr 24Apr 20Apr 15Apr 11Apr 5Mar 31Mar 25
32°FApr 14Apr 1Mar 25Mar 20Mar 14Mar 9Mar 2Feb 26Feb 18
28°FMar 8Mar 1Feb 25Feb 19Feb 15Feb 7Jan 27Jan 8Dec 26
24°FFeb 20Feb 12Jan 31Jan 16Jan 6Dec 31Dec 24Dec 15Dec 5
20°FFeb 14Jan 31Jan 10Dec 31Dec 28Dec 23Dec 18Dec 12Dec 4
16°FJan 7Dec 30Dec 28Dec 24Dec 22Dec 19Dec 14Dec 10Dec 4

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°FOct 8Oct 15Oct 20Oct 25Oct 28Nov 1Nov 5Nov 11Nov 20
32°FOct 27Nov 2Nov 7Nov 12Nov 18Nov 24Nov 30Dec 6Dec 15
28°FNov 8Nov 19Nov 28Dec 4Dec 10Dec 16Dec 22Jan 1Jan 16
24°FNov 22Dec 1Dec 8Dec 15Dec 21Dec 27Jan 2Jan 14Feb 8
20°FDec 1Dec 9Dec 13Dec 19Dec 23Dec 28Jan 2Jan 18Feb 9
16°FDec 3Dec 9Dec 13Dec 16Dec 20Dec 23Dec 26Dec 29Jan 2

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°F226214206200195189183176168
32°F286273263254248241233223210
28°F345332319310302295285276260
24°F365365365358348339331318308
20°F365365365365365365364352335
16°F365365365365365365365365364

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
96% of years
24°F or colder
66% of years
20°F or colder
33% of years
16°F or colder
11% 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
4,149
Cooling degree days, base 65°F
494
Growing degree days, base 40°F
5,632
Growing degree days, base 45°F
4,079
Growing degree days, base 50°F
2,778
Growing degree days, base 55°F
1,773
Growing degree days, base 60°F
1,022

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January688016
February568015
March519041
April394190
May21913262
June8953414
July12170623
August10185640
September7269447
October3133173
November543039
December721019

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 0.6 km from Lebanon. 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 USC00354819 (Lebanon). Public domain.