Spring Grove climate

Spring Grove Frost Dates and Growing Season

NOAA 1991-2020 normals for Caledonia, 13.2 km from Spring Grove, elevation 1166 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Caledonia. 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 29 and the first fall freeze around October 10, a growing season of about 165 days.

Median at 36°F
last May 7, first October 1
Median at 32°F
last April 29, first October 10
Median at 28°F
last April 18, first October 23

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 20May 15May 12May 10May 7May 5May 3May 1Apr 26
32°FMay 11May 7May 3May 1Apr 29Apr 26Apr 23Apr 19Apr 14
28°FMay 2Apr 29Apr 25Apr 21Apr 18Apr 15Apr 12Apr 8Apr 4
24°FApr 24Apr 18Apr 15Apr 11Apr 8Apr 5Apr 3Apr 1Mar 24
20°FApr 15Apr 8Apr 4Apr 2Apr 1Mar 29Mar 24Mar 20Mar 14
16°FApr 5Apr 1Mar 30Mar 26Mar 22Mar 19Mar 16Mar 12Mar 8

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 18Sep 22Sep 26Sep 28Oct 1Oct 3Oct 6Oct 9Oct 14
32°FSep 28Oct 1Oct 5Oct 8Oct 10Oct 13Oct 17Oct 20Oct 24
28°FOct 9Oct 13Oct 18Oct 20Oct 23Oct 25Oct 28Oct 31Nov 4
24°FOct 20Oct 25Oct 28Oct 30Nov 1Nov 3Nov 7Nov 10Nov 15
20°FOct 31Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17Nov 20Nov 25
16°FNov 5Nov 9Nov 13Nov 16Nov 19Nov 22Nov 25Nov 28Dec 3

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°F163157153148145142138133126
32°F184178172168165160157152146
28°F205199195190187183178174166
24°F225217213209205201197192185
20°F245238233228223220216212205
16°F261254249244241236232226220

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
7,641
Cooling degree days, base 65°F
587
Growing degree days, base 40°F
4,534
Growing degree days, base 45°F
3,507
Growing degree days, base 50°F
2,593
Growing degree days, base 55°F
1,795
Growing degree days, base 60°F
1,120

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51700
February1,25600
March1,020011
April592263
May26132263
June49128530
July10210665
August24154595
September16355353
October5125102
November914011
December1,32400

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 13.2 km from Spring Grove. 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 USC00211198 (Caledonia). Public domain.