Richmond climate

Richmond Frost Dates and Growing Season

NOAA 1991-2020 normals for Whitewater, 15.2 km from Richmond, elevation 875 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Whitewater. 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 2 and the first fall freeze around October 9, a growing season of about 157 days.

Median at 36°F
last May 16, first September 30
Median at 32°F
last May 2, first October 9
Median at 28°F
last April 20, first October 22

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°FJun 1May 27May 23May 19May 16May 13May 9May 5Apr 30
32°FMay 20May 15May 10May 6May 2Apr 30Apr 27Apr 23Apr 18
28°FMay 6May 1Apr 27Apr 24Apr 20Apr 18Apr 14Apr 11Apr 6
24°FApr 23Apr 18Apr 14Apr 11Apr 8Apr 6Apr 3Mar 31Mar 25
20°FApr 13Apr 7Apr 4Apr 2Mar 31Mar 28Mar 24Mar 20Mar 14
16°FApr 3Mar 31Mar 27Mar 24Mar 20Mar 17Mar 14Mar 10Mar 5

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 16Sep 21Sep 24Sep 27Sep 30Oct 1Oct 4Oct 8Oct 12
32°FSep 25Sep 30Oct 3Oct 6Oct 9Oct 13Oct 15Oct 19Oct 24
28°FOct 5Oct 11Oct 16Oct 19Oct 22Oct 25Oct 28Oct 31Nov 4
24°FOct 20Oct 26Oct 30Nov 1Nov 2Nov 5Nov 8Nov 12Nov 18
20°FNov 1Nov 3Nov 6Nov 10Nov 14Nov 17Nov 20Nov 24Nov 29
16°FNov 7Nov 13Nov 17Nov 20Nov 23Nov 26Nov 29Dec 2Dec 9

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°F154148142138134130126122116
32°F179172166161157152148143136
28°F205197191186182177172165159
24°F228221216212207203199194184
20°F250243238233228225219215209
16°F269262256251247243238232224

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
7,158
Cooling degree days, base 65°F
621
Growing degree days, base 40°F
4,645
Growing degree days, base 45°F
3,582
Growing degree days, base 50°F
2,646
Growing degree days, base 55°F
1,838
Growing degree days, base 60°F
1,157

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,41200
February1,17601
March957115
April575365
May26638265
June56137532
July13211663
August26162601
September15163369
October4707118
November836016
December1,22101

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 15.2 km from Richmond. 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 USC00479190 (Whitewater). Public domain.