Rockwood climate

Rockwood Frost Dates and Growing Season

NOAA 1991-2020 normals for Newport 4SSE, 13.8 km from Rockwood, elevation 578 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Newport 4SSE. 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 27 and the first fall freeze around October 22, a growing season of about 177 days.

Median at 36°F
last May 7, first October 10
Median at 32°F
last April 27, first October 22
Median at 28°F
last April 15, 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 23May 18May 14May 10May 7May 3Apr 30Apr 28Apr 23
32°FMay 12May 7May 2Apr 30Apr 27Apr 23Apr 20Apr 17Apr 12
28°FMay 1Apr 25Apr 21Apr 18Apr 15Apr 11Apr 8Apr 4Apr 1
24°FApr 17Apr 12Apr 8Apr 5Apr 2Mar 31Mar 28Mar 23Mar 19
20°FApr 5Mar 31Mar 29Mar 25Mar 23Mar 19Mar 17Mar 14Mar 9
16°FMar 29Mar 24Mar 20Mar 17Mar 14Mar 11Mar 8Mar 4Feb 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°FSep 29Oct 2Oct 5Oct 7Oct 10Oct 12Oct 15Oct 19Oct 23
32°FOct 8Oct 13Oct 17Oct 20Oct 22Oct 25Oct 28Oct 31Nov 4
28°FOct 21Oct 26Oct 30Nov 1Nov 3Nov 5Nov 8Nov 11Nov 16
24°FNov 1Nov 4Nov 7Nov 10Nov 12Nov 16Nov 19Nov 24Nov 29
20°FNov 8Nov 13Nov 17Nov 21Nov 25Nov 28Dec 2Dec 7Dec 15
16°FNov 16Nov 23Nov 29Dec 2Dec 6Dec 9Dec 15Dec 21Dec 26

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°F174167162158154150146142136
32°F196190185181177172168163156
28°F220213207203199195190186179
24°F245237232228224220215210204
20°F270263257251247242237231225
16°F293284278274269264259253244

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
6,406
Cooling degree days, base 65°F
693
Growing degree days, base 40°F
4,917
Growing degree days, base 45°F
3,801
Growing degree days, base 50°F
2,827
Growing degree days, base 55°F
1,991
Growing degree days, base 60°F
1,276

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24500
February1,07100
March930010
April552157
May25027262
June38139552
July6237696
August8201657
September9481438
October4098139
November743015
December1,06201

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 13.8 km from Rockwood. 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 USC00205822 (Newport 4SSE). Public domain.