New Sharon climate

New Sharon Frost Dates and Growing Season

NOAA 1991-2020 normals for Oskaloosa, 16.5 km from New Sharon, elevation 830 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oskaloosa. 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 April 21 and the first fall freeze around October 16, a growing season of about 176 days.

Median at 36°F
last May 1, first October 4
Median at 32°F
last April 21, first October 16
Median at 28°F
last April 11, first October 27

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 14May 9May 6May 4May 1Apr 29Apr 26Apr 23Apr 18
32°FMay 4May 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 12Apr 8
28°FApr 26Apr 21Apr 16Apr 14Apr 11Apr 9Apr 6Apr 3Mar 29
24°FApr 17Apr 12Apr 8Apr 5Apr 3Mar 31Mar 28Mar 23Mar 17
20°FApr 8Apr 3Mar 31Mar 27Mar 23Mar 20Mar 17Mar 13Mar 7
16°FMar 31Mar 25Mar 20Mar 17Mar 14Mar 11Mar 7Mar 4Feb 28

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 21Sep 26Sep 29Oct 1Oct 4Oct 7Oct 11Oct 14Oct 19
32°FSep 29Oct 5Oct 9Oct 13Oct 16Oct 19Oct 22Oct 25Oct 29
28°FOct 10Oct 18Oct 21Oct 24Oct 27Oct 30Nov 1Nov 3Nov 8
24°FOct 23Oct 28Oct 31Nov 1Nov 4Nov 7Nov 9Nov 13Nov 19
20°FNov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 19Nov 23Nov 30
16°FNov 7Nov 10Nov 14Nov 17Nov 21Nov 25Nov 28Dec 1Dec 7

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°F175168164160156152148144137
32°F196189185180176172168163155
28°F217209205201198193189184175
24°F237230224220215211207203195
20°F258250245240235229225219213
16°F275267261255251248244238231

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
6,366
Cooling degree days, base 65°F
958
Growing degree days, base 40°F
5,478
Growing degree days, base 45°F
4,328
Growing degree days, base 50°F
3,296
Growing degree days, base 55°F
2,388
Growing degree days, base 60°F
1,604

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,35000
February1,09502
March829232
April4526119
May16859365
June20204634
July2316780
August7252710
September98104459
October39114170
November783025
December1,17201

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 16.5 km from New Sharon. 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 USC00136327 (Oskaloosa). Public domain.