Sweetser climate

Sweetser Frost Dates and Growing Season

NOAA 1991-2020 normals for Marion 2 N, 9.4 km from Sweetser, elevation 790 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Marion 2 N. 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 26 and the first fall freeze around October 20, a growing season of about 175 days.

Median at 36°F
last May 7, first October 9
Median at 32°F
last April 26, first October 20
Median at 28°F
last April 14, first November 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°FMay 22May 17May 13May 10May 7May 4May 1Apr 27Apr 23
32°FMay 12May 7May 3Apr 30Apr 26Apr 22Apr 19Apr 16Apr 11
28°FApr 30Apr 23Apr 19Apr 17Apr 14Apr 10Apr 7Apr 4Mar 31
24°FApr 17Apr 12Apr 7Apr 4Apr 2Mar 31Mar 28Mar 23Mar 18
20°FApr 5Apr 1Mar 30Mar 26Mar 23Mar 19Mar 15Mar 11Mar 4
16°FMar 28Mar 23Mar 19Mar 15Mar 12Mar 9Mar 5Mar 1Feb 24

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 26Oct 1Oct 4Oct 6Oct 9Oct 11Oct 14Oct 17Oct 21
32°FOct 5Oct 11Oct 15Oct 17Oct 20Oct 22Oct 25Oct 28Nov 1
28°FOct 17Oct 23Oct 26Oct 29Nov 1Nov 2Nov 5Nov 8Nov 14
24°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 14Nov 18Nov 22Nov 28
20°FNov 7Nov 11Nov 15Nov 18Nov 22Nov 26Nov 30Dec 4Dec 12
16°FNov 13Nov 21Nov 25Nov 29Dec 1Dec 6Dec 11Dec 17Dec 23

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°F173167163158154150146141133
32°F195189184180175171167162154
28°F220213208204200195191185177
24°F245237232227223219215210204
20°F270260254248244240235230223
16°F294283276271266260254249241

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
6,079
Cooling degree days, base 65°F
813
Growing degree days, base 40°F
5,319
Growing degree days, base 45°F
4,151
Growing degree days, base 50°F
3,119
Growing degree days, base 55°F
2,216
Growing degree days, base 60°F
1,445

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22902
February1,02902
March837130
April4686112
May19356343
June30180600
July5257718
August10204659
September9594451
October38414168
November729030
December1,06904

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 9.4 km from Sweetser. 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 USC00125337 (Marion 2 N). Public domain.