Sand Rock climate

Sand Rock Frost Dates and Growing Season

NOAA 1991-2020 normals for Centre, 12.9 km from Sand Rock, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Centre. 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 6 and the first fall freeze around October 31, a growing season of about 207 days.

Median at 36°F
last April 18, first October 23
Median at 32°F
last April 6, first October 31
Median at 28°F
last March 24, first November 9

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 18Apr 15Apr 12Apr 8Apr 2
32°FApr 22Apr 16Apr 13Apr 9Apr 6Apr 2Mar 30Mar 26Mar 20
28°FApr 10Apr 5Apr 1Mar 29Mar 24Mar 20Mar 16Mar 10Mar 3
24°FMar 31Mar 24Mar 18Mar 14Mar 9Mar 4Feb 28Feb 24Feb 16
20°FMar 16Mar 9Mar 3Feb 28Feb 24Feb 19Feb 13Feb 5Jan 29
16°FMar 6Feb 27Feb 20Feb 13Feb 6Feb 1Jan 28Jan 20Jan 7

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 11Oct 15Oct 18Oct 21Oct 23Oct 25Oct 28Nov 1Nov 4
32°FOct 18Oct 22Oct 26Oct 28Oct 31Nov 2Nov 5Nov 8Nov 13
28°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 11Nov 15Nov 20Nov 27
24°FNov 5Nov 10Nov 14Nov 17Nov 21Nov 25Dec 1Dec 4Dec 13
20°FNov 15Nov 22Nov 29Dec 3Dec 8Dec 14Dec 23Dec 31Jan 7
16°FDec 1Dec 11Dec 21Dec 27Jan 1Jan 5Jan 9Jan 16Jan 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°F206199193190186182178172166
32°F230221216211207203199193186
28°F257248242236231226221214206
24°F287278271265259252247241232
20°F322311304296290284277268257
16°F359346334329322314306296285

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
94% 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
3,421
Cooling degree days, base 65°F
1,509
Growing degree days, base 40°F
7,508
Growing degree days, base 45°F
5,994
Growing degree days, base 50°F
4,626
Growing degree days, base 55°F
3,421
Growing degree days, base 60°F
2,385

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January784025
February608039
March4313132
April20024289
May58123530
June1295744
July0408873
August0386851
September13222658
October16945353
November465392
December693041

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 12.9 km from Sand Rock. 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 USC00011490 (Centre). Public domain.