Lookout Mountain climate

Lookout Mountain Frost Dates and Growing Season

NOAA 1991-2020 normals for Lookout Mtn-Point Park, 3.7 km from Lookout Mountain, elevation 2110 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lookout Mtn-Point Park. 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 31 and the first fall freeze around November 6, a growing season of about 219 days.

Median at 36°F
last April 12, first October 29
Median at 32°F
last March 31, first November 6
Median at 28°F
last March 21, first November 17

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°FApr 27Apr 22Apr 19Apr 15Apr 12Apr 9Apr 5Apr 1Mar 27
32°FApr 18Apr 12Apr 7Apr 3Mar 31Mar 29Mar 25Mar 20Mar 15
28°FApr 6Mar 31Mar 28Mar 24Mar 21Mar 17Mar 13Mar 9Mar 1
24°FMar 27Mar 22Mar 17Mar 13Mar 9Mar 6Mar 1Feb 25Feb 15
20°FMar 20Mar 12Mar 7Mar 3Feb 28Feb 22Feb 15Feb 7Jan 31
16°FMar 11Mar 3Feb 26Feb 19Feb 10Feb 4Jan 31Jan 24Jan 14

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 16Oct 21Oct 24Oct 26Oct 29Oct 31Nov 2Nov 6Nov 11
32°FOct 24Oct 29Nov 1Nov 3Nov 6Nov 9Nov 13Nov 19Nov 26
28°FNov 2Nov 6Nov 9Nov 13Nov 17Nov 21Nov 27Dec 1Dec 7
24°FNov 10Nov 16Nov 22Nov 26Dec 1Dec 3Dec 8Dec 14Dec 24
20°FNov 21Nov 29Dec 3Dec 9Dec 15Dec 21Dec 27Jan 1Jan 11
16°FDec 3Dec 11Dec 20Dec 26Dec 31Jan 3Jan 9Jan 15Jan 22

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°F220211206202198194190186179
32°F244236230224219215210205196
28°F269261254247243238232225217
24°F295286278272266260254248239
20°F324312304299291285278270260
16°F352336329322315307301294284

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
97% 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
3,918
Cooling degree days, base 65°F
1,182
Growing degree days, base 40°F
6,868
Growing degree days, base 45°F
5,420
Growing degree days, base 50°F
4,113
Growing degree days, base 55°F
2,973
Growing degree days, base 60°F
1,997

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January863018
February689023
March5173101
April24825259
May8197482
June8236678
July0329794
August2296759
September29163584
October21731302
November503285
December761030

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 3.7 km from Lookout Mountain. 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 USC00405431 (Lookout Mtn-Point Park). Public domain.