Rutledge climate

Rutledge Frost Dates and Growing Season

NOAA 1991-2020 normals for Morristown WFO, 16.1 km from Rutledge, elevation 1320 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Morristown WFO. 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 4, a growing season of about 217 days.

Median at 36°F
last April 14, first October 26
Median at 32°F
last March 31, first November 4
Median at 28°F
last March 21, first November 14

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 2Apr 25Apr 21Apr 16Apr 14Apr 10Apr 6Apr 2Mar 29
32°FApr 18Apr 12Apr 6Apr 2Mar 31Mar 29Mar 25Mar 21Mar 14
28°FApr 5Mar 31Mar 28Mar 25Mar 21Mar 17Mar 13Mar 8Mar 2
24°FMar 27Mar 21Mar 15Mar 11Mar 7Mar 3Feb 27Feb 22Feb 13
20°FMar 17Mar 10Mar 4Feb 28Feb 23Feb 18Feb 11Feb 4Jan 29
16°FMar 8Feb 27Feb 18Feb 12Feb 6Feb 1Jan 28Jan 21Jan 12

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 13Oct 17Oct 21Oct 24Oct 26Oct 28Oct 31Nov 3Nov 7
32°FOct 22Oct 27Oct 31Nov 1Nov 4Nov 6Nov 9Nov 12Nov 18
28°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 18Nov 22Nov 26Dec 2
24°FNov 10Nov 14Nov 19Nov 23Nov 26Dec 1Dec 4Dec 10Dec 19
20°FNov 20Nov 27Dec 2Dec 6Dec 11Dec 18Dec 24Dec 29Jan 5
16°FDec 4Dec 11Dec 20Dec 26Dec 31Jan 3Jan 8Jan 14Jan 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°F218209203199195190185179172
32°F242233227222217213208203195
28°F265257250245240236230224218
24°F295284277271265260253246239
20°F323313306300293287279272261
16°F351337331325320313306300288

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
3,773
Cooling degree days, base 65°F
1,314
Growing degree days, base 40°F
7,101
Growing degree days, base 45°F
5,634
Growing degree days, base 50°F
4,318
Growing degree days, base 55°F
3,163
Growing degree days, base 60°F
2,161

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January854020
February661028
March4873113
April22326279
May68110508
June3258705
July0358823
August0340804
September22184612
October20233314
November500285
December753027

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 16.1 km from Rutledge. 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 USC00406272 (Morristown WFO). Public domain.