Rusk County climate

Rusk County Frost Dates and Growing Season

NOAA 1991-2020 normals for Ladysmith 3W, 1.3 km from Rusk County, elevation 1130 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ladysmith 3W. 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 27 and the first fall freeze around September 22, a growing season of about 117 days.

Median at 36°F
last June 7, first September 10
Median at 32°F
last May 27, first September 22
Median at 28°F
last May 15, first October 1

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°FJul 1Jun 21Jun 15Jun 11Jun 7Jun 4Jun 2May 30May 24
32°FJun 8Jun 4Jun 2May 31May 27May 24May 21May 18May 14
28°FMay 30May 25May 21May 18May 15May 12May 9May 5May 1
24°FMay 18May 13May 9May 5May 3Apr 30Apr 28Apr 23Apr 18
20°FMay 6May 2Apr 29Apr 25Apr 22Apr 18Apr 15Apr 10Apr 5
16°FApr 26Apr 21Apr 17Apr 13Apr 10Apr 6Apr 3Apr 1Mar 26

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 24Sep 1Sep 3Sep 6Sep 10Sep 13Sep 16Sep 20Sep 24
32°FSep 6Sep 12Sep 16Sep 19Sep 22Sep 25Sep 28Oct 1Oct 4
28°FSep 17Sep 22Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 16
24°FSep 27Oct 2Oct 6Oct 9Oct 12Oct 16Oct 20Oct 24Oct 29
20°FOct 10Oct 16Oct 20Oct 23Oct 27Oct 30Nov 1Nov 5Nov 12
16°FOct 22Oct 27Oct 31Nov 2Nov 6Nov 10Nov 14Nov 18Nov 24

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°F113106100969287817565
32°F13613012512111711310910396
28°F158152146142138134130124117
24°F185176171166161157154148140
20°F210201196191187182176170164
16°F233225219214210205200195186

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
8,746
Cooling degree days, base 65°F
204
Growing degree days, base 40°F
3,526
Growing degree days, base 45°F
2,583
Growing degree days, base 50°F
1,770
Growing degree days, base 55°F
1,086
Growing degree days, base 60°F
548

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,59800
February1,35200
March1,13507
April710029
May3729162
June12138368
July5979485
August8657437
September26819230
October631249
November1,01403
December1,40100

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 1.3 km from Rusk County. 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 USC00474391 (Ladysmith 3W). Public domain.