Sparta climate

Sparta Frost Dates and Growing Season

NOAA 1991-2020 normals for Sparta, 0.9 km from Sparta, elevation 782 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sparta. 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 9 and the first fall freeze around October 1, a growing season of about 144 days.

Median at 36°F
last May 19, first September 23
Median at 32°F
last May 9, first October 1
Median at 28°F
last April 29, first October 11

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 31May 27May 24May 22May 19May 16May 14May 11May 6
32°FMay 22May 18May 15May 12May 9May 6May 4May 1Apr 26
28°FMay 13May 8May 4May 1Apr 29Apr 27Apr 23Apr 20Apr 15
24°FMay 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 11Apr 7Apr 3
20°FApr 22Apr 16Apr 12Apr 9Apr 6Apr 4Apr 2Mar 31Mar 23
16°FApr 10Apr 6Apr 3Apr 1Mar 30Mar 26Mar 23Mar 18Mar 13

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°FSep 10Sep 14Sep 18Sep 20Sep 23Sep 26Sep 28Oct 1Oct 5
32°FSep 18Sep 23Sep 26Sep 29Oct 1Oct 3Oct 6Oct 9Oct 13
28°FSep 27Oct 1Oct 5Oct 8Oct 11Oct 13Oct 16Oct 19Oct 24
24°FOct 7Oct 13Oct 17Oct 19Oct 22Oct 24Oct 27Oct 30Nov 3
20°FOct 19Oct 24Oct 27Oct 31Nov 1Nov 3Nov 6Nov 9Nov 16
16°FOct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 22Nov 28

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°F142137133129125121118114107
32°F162156152148144141138133127
28°F183176172167163160155151142
24°F205200195190186182177173166
20°F227220215211207204199194187
16°F248241235232228224220215209

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
7,935
Cooling degree days, base 65°F
536
Growing degree days, base 40°F
4,323
Growing degree days, base 45°F
3,327
Growing degree days, base 50°F
2,443
Growing degree days, base 55°F
1,678
Growing degree days, base 60°F
1,036

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,54800
February1,27700
March1,041012
April626254
May28728243
June62117506
July17195643
August34142573
September19147322
October562481
November94208
December1,34800

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 0.9 km from Sparta. 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 USC00477997 (Sparta). Public domain.