Spring Hill climate

Spring Hill Frost Dates and Growing Season

NOAA 1991-2020 normals for Hillsdale Lake, 10.4 km from Spring Hill, elevation 1010 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hillsdale Lake. 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 9 and the first fall freeze around October 31, a growing season of about 204 days.

Median at 36°F
last April 19, first October 21
Median at 32°F
last April 9, first October 31
Median at 28°F
last April 1, first November 8

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 3Apr 29Apr 25Apr 22Apr 19Apr 16Apr 13Apr 10Apr 6
32°FApr 23Apr 18Apr 14Apr 11Apr 9Apr 6Apr 4Apr 1Mar 27
28°FApr 13Apr 9Apr 6Apr 3Apr 1Mar 30Mar 26Mar 22Mar 16
24°FApr 5Apr 1Mar 29Mar 25Mar 22Mar 18Mar 15Mar 10Mar 4
20°FMar 29Mar 23Mar 19Mar 16Mar 12Mar 9Mar 5Mar 1Feb 25
16°FMar 21Mar 16Mar 11Mar 8Mar 4Mar 1Feb 26Feb 22Feb 15

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 7Oct 13Oct 17Oct 19Oct 21Oct 23Oct 26Oct 29Nov 1
32°FOct 17Oct 22Oct 25Oct 28Oct 31Nov 1Nov 4Nov 8Nov 13
28°FOct 27Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 17Nov 23
24°FNov 2Nov 6Nov 10Nov 14Nov 16Nov 19Nov 23Nov 28Dec 2
20°FNov 9Nov 15Nov 19Nov 23Nov 26Nov 30Dec 2Dec 5Dec 10
16°FNov 17Nov 23Nov 27Dec 1Dec 3Dec 6Dec 10Dec 15Dec 21

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°F202197191187183180175170163
32°F221215211207204199196191183
28°F241234229224221217213208202
24°F261254249244239235231225218
20°F279271265261256252247241233
16°F299290284279274269265258250

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
5,052
Cooling degree days, base 65°F
1,382
Growing degree days, base 40°F
6,494
Growing degree days, base 45°F
5,208
Growing degree days, base 50°F
4,056
Growing degree days, base 55°F
3,029
Growing degree days, base 60°F
2,137

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12002
February88409
March649368
April33312191
May10699461
June7279721
July0417882
August1378842
September49168570
October28527251
November637154
December97906

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 10.4 km from Spring Hill. 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 USC00143686 (Hillsdale Lake). Public domain.