Rocky Mount climate

Rocky Mount Frost Dates and Growing Season

NOAA 1991-2020 normals for Rocky Mt, 2.4 km from Rocky Mount, elevation 1315 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rocky Mt. 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 20 and the first fall freeze around October 25, a growing season of about 188 days.

Median at 36°F
last April 30, first October 16
Median at 32°F
last April 20, first October 25
Median at 28°F
last April 3, first November 3

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 16May 10May 6May 2Apr 30Apr 28Apr 23Apr 20Apr 16
32°FMay 8May 1Apr 27Apr 23Apr 20Apr 16Apr 13Apr 8Apr 1
28°FApr 23Apr 17Apr 11Apr 7Apr 3Mar 31Mar 28Mar 23Mar 18
24°FApr 7Apr 2Mar 29Mar 24Mar 20Mar 17Mar 13Mar 7Feb 28
20°FMar 23Mar 17Mar 13Mar 9Mar 4Feb 28Feb 25Feb 20Feb 12
16°FMar 16Mar 6Mar 1Feb 25Feb 21Feb 14Feb 8Feb 3Jan 27

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°FOct 4Oct 8Oct 11Oct 14Oct 16Oct 19Oct 22Oct 25Oct 29
32°FOct 11Oct 15Oct 20Oct 22Oct 25Oct 28Oct 31Nov 2Nov 5
28°FOct 20Oct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 15
24°FNov 1Nov 4Nov 8Nov 10Nov 13Nov 16Nov 20Nov 26Dec 2
20°FNov 10Nov 15Nov 20Nov 25Nov 29Dec 2Dec 7Dec 14Dec 25
16°FNov 25Dec 2Dec 9Dec 16Dec 25Jan 1Jan 5Jan 12Jan 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°F188181177172168164160156149
32°F210203197193188185180175167
28°F236227222218214210204198191
24°F265256250244239234229224216
20°F299288281276270264258252243
16°F333323314307302296289281270

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
98% 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
4,290
Cooling degree days, base 65°F
1,066
Growing degree days, base 40°F
6,373
Growing degree days, base 45°F
4,980
Growing degree days, base 50°F
3,754
Growing degree days, base 55°F
2,701
Growing degree days, base 60°F
1,805

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January87709
February728014
March585269
April29717208
May11278434
June13215652
July1333797
August2284747
September50119519
October27317235
November562155
December791015

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 2.4 km from Rocky Mount. 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 USC00447338 (Rocky Mt). Public domain.