Carroll climate

Carroll Frost Dates and Growing Season

NOAA 1991-2020 normals for Lancaster Fairfield AP, 6.1 km from Carroll, elevation 869 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lancaster Fairfield AP. 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 13, a growing season of about 169 days.

Median at 36°F
last May 5, first October 3
Median at 32°F
last April 26, first October 13
Median at 28°F
last April 15, first October 24

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 18May 13May 9May 5May 1Apr 29Apr 26Apr 21
32°FMay 12May 6May 2Apr 29Apr 26Apr 23Apr 20Apr 17Apr 12
28°FMay 2Apr 26Apr 21Apr 18Apr 15Apr 12Apr 8Apr 5Mar 31
24°FApr 18Apr 12Apr 8Apr 5Apr 2Mar 31Mar 27Mar 22Mar 17
20°FApr 5Apr 1Mar 29Mar 25Mar 21Mar 18Mar 14Mar 10Mar 4
16°FMar 28Mar 22Mar 17Mar 13Mar 10Mar 7Mar 3Feb 28Feb 21

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 24Sep 28Oct 1Oct 3Oct 5Oct 8Oct 10Oct 15
32°FOct 1Oct 5Oct 7Oct 11Oct 13Oct 16Oct 19Oct 23Oct 28
28°FOct 11Oct 16Oct 19Oct 22Oct 24Oct 28Oct 31Nov 2Nov 7
24°FOct 20Oct 25Oct 30Nov 1Nov 4Nov 6Nov 10Nov 15Nov 20
20°FNov 2Nov 5Nov 9Nov 13Nov 17Nov 20Nov 24Dec 1Dec 5
16°FNov 10Nov 16Nov 21Nov 26Dec 1Dec 3Dec 8Dec 15Dec 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°F167161156152149144140135129
32°F189183177173169166161156149
28°F214205201197193189184179171
24°F240230225220216212208203196
20°F266257249245240236230225217
16°F293284276271266260254247239

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
5,472
Cooling degree days, base 65°F
824
Growing degree days, base 40°F
5,590
Growing degree days, base 45°F
4,351
Growing degree days, base 50°F
3,252
Growing degree days, base 55°F
2,297
Growing degree days, base 60°F
1,486

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11607
February92609
March744143
April3939152
May15467385
June20182612
July3260722
August8208665
September9185446
October37611166
November681035
December961011

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 6.1 km from Carroll. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00053844 (Lancaster Fairfield AP). Public domain.