Richland County climate

Richland County Frost Dates and Growing Season

NOAA 1991-2020 normals for Richland Ctr, 5.9 km from Richland County, elevation 728 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Richland Ctr. 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 May 5 and the first fall freeze around October 6, a growing season of about 154 days.

Median at 36°F
last May 16, first September 29
Median at 32°F
last May 5, first October 6
Median at 28°F
last April 25, first October 17

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 29May 25May 21May 19May 16May 13May 10May 6May 1
32°FMay 19May 14May 11May 7May 5May 2Apr 30Apr 26Apr 21
28°FMay 9May 4May 1Apr 28Apr 25Apr 22Apr 18Apr 15Apr 10
24°FApr 29Apr 24Apr 20Apr 16Apr 13Apr 10Apr 7Apr 4Mar 31
20°FApr 18Apr 12Apr 8Apr 5Apr 3Apr 1Mar 28Mar 23Mar 17
16°FApr 6Apr 2Mar 31Mar 27Mar 23Mar 20Mar 17Mar 13Mar 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 17Sep 21Sep 24Sep 27Sep 29Oct 1Oct 3Oct 5Oct 9
32°FSep 24Sep 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 14Oct 18
28°FOct 2Oct 8Oct 11Oct 14Oct 17Oct 20Oct 22Oct 25Oct 29
24°FOct 14Oct 19Oct 22Oct 25Oct 27Oct 30Nov 1Nov 4Nov 9
20°FOct 26Oct 31Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 23
16°FNov 3Nov 6Nov 10Nov 14Nov 17Nov 20Nov 24Nov 27Dec 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°F153146141137134131127123117
32°F172166161157154150146142135
28°F194188182178174169166161154
24°F217209205200197193188182176
20°F240233228223219215211205199
16°F261253248244239235230225217

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
7,498
Cooling degree days, base 65°F
522
Growing degree days, base 40°F
4,425
Growing degree days, base 45°F
3,389
Growing degree days, base 50°F
2,479
Growing degree days, base 55°F
1,694
Growing degree days, base 60°F
1,036

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,47400
February1,22200
March988113
April592152
May27224243
June54112509
July13191643
August26142581
September16747339
October518489
November88808
December1,28301

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 5.9 km from Richland County. 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 USC00477158 (Richland Ctr). Public domain.