Greenville climate

Greenville Frost Dates and Growing Season

NOAA 1991-2020 normals for Canyon Dam, 12.2 km from Greenville, elevation 4560 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Canyon Dam. 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 18 and the first fall freeze around October 8, a growing season of about 143 days.

Median at 36°F
last June 7, first September 24
Median at 32°F
last May 18, first October 8
Median at 28°F
last April 26, first October 26

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 23Jun 17Jun 14Jun 10Jun 7Jun 4Jun 1May 28May 21
32°FJun 9Jun 3May 29May 23May 18May 13May 9May 4Apr 30
28°FMay 16May 9May 2Apr 29Apr 26Apr 23Apr 20Apr 16Apr 10
24°FApr 26Apr 19Apr 15Apr 11Apr 8Apr 5Mar 31Mar 25Mar 16
20°FApr 6Mar 28Mar 21Mar 14Mar 9Mar 4Feb 27Feb 20Feb 10
16°FMar 11Mar 4Feb 26Feb 21Feb 15Feb 9Feb 2Jan 21Jan 4

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

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°F129122116111106101979184
32°F169159153149143137131124115
28°F204197191186181177171165156
24°F245234226222216211207200192
20°F289279270263257251245237227
16°F336324314306297291283274263

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
99% 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
6,073
Cooling degree days, base 65°F
286
Growing degree days, base 40°F
4,093
Growing degree days, base 45°F
2,984
Growing degree days, base 50°F
2,062
Growing degree days, base 55°F
1,312
Growing degree days, base 60°F
712

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January97700
February81900
March78302
April606025
May3624155
June14834341
July27129567
August3494526
September13425345
October440199
November75503
December99000

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 12.2 km from Greenville. 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 USC00041497 (Canyon Dam). Public domain.