Richmond climate

Richmond Frost Dates and Growing Season

NOAA 1991-2020 normals for Richmond 4 Nnw, 8.4 km from Richmond, elevation 765 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Richmond 4 Nnw. 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 1 and the first fall freeze around October 20, a growing season of about 170 days.

Median at 36°F
last May 10, first October 6
Median at 32°F
last May 1, first October 20
Median at 28°F
last April 19, first November 1

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 25May 20May 17May 13May 10May 6May 3Apr 30Apr 27
32°FMay 17May 11May 6May 3May 1Apr 28Apr 25Apr 22Apr 18
28°FMay 4Apr 30Apr 26Apr 22Apr 19Apr 17Apr 14Apr 10Apr 5
24°FApr 19Apr 16Apr 13Apr 9Apr 6Apr 3Apr 1Mar 29Mar 21
20°FApr 8Apr 3Mar 31Mar 30Mar 27Mar 23Mar 19Mar 15Mar 10
16°FMar 31Mar 27Mar 23Mar 19Mar 16Mar 13Mar 10Mar 6Mar 2

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

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°F166161155152149144141136131
32°F191184179175170167162157150
28°F214208203198194190185180171
24°F242234229224220216212206199
20°F267258252247243238233229222
16°F286278272268264259254248241

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
6,785
Cooling degree days, base 65°F
649
Growing degree days, base 40°F
4,734
Growing degree days, base 45°F
3,653
Growing degree days, base 50°F
2,709
Growing degree days, base 55°F
1,890
Growing degree days, base 60°F
1,197

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,29700
February1,13500
March977112
April576262
May25233273
June49139541
July9242699
August22168611
September13459379
October4496117
November777014
December1,10801

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 8.4 km from Richmond. 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 USC00206982 (Richmond 4 Nnw). Public domain.