Phillips County climate

Phillips County Frost Dates and Growing Season

NOAA 1991-2020 normals for Holyoke, 5.6 km from Phillips County, elevation 3780 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Holyoke. 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 11 and the first fall freeze around October 3, a growing season of about 144 days.

Median at 36°F
last May 20, first September 25
Median at 32°F
last May 11, first October 3
Median at 28°F
last May 1, first October 12

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 2May 28May 25May 22May 20May 17May 15May 12May 9
32°FMay 23May 18May 15May 13May 11May 9May 7May 4Apr 30
28°FMay 14May 10May 7May 4May 1Apr 29Apr 26Apr 22Apr 17
24°FMay 5Apr 30Apr 27Apr 23Apr 20Apr 18Apr 15Apr 11Apr 6
20°FApr 24Apr 19Apr 15Apr 11Apr 8Apr 4Apr 1Mar 29Mar 22
16°FApr 15Apr 9Apr 5Apr 1Mar 30Mar 25Mar 22Mar 16Mar 9

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

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°F141136132129126123119114108
32°F160154150147144140136131125
28°F179173169165162158154149144
24°F198191187182179176171167160
20°F224216211205201196191186179
16°F246239231227222216211206197

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
6,546
Cooling degree days, base 65°F
700
Growing degree days, base 40°F
4,831
Growing degree days, base 45°F
3,717
Growing degree days, base 50°F
2,755
Growing degree days, base 55°F
1,939
Growing degree days, base 60°F
1,253

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17300
February99802
March825018
April557165
May28124251
June52136535
July7264722
August17206654
September13866389
October4973108
November842011
December1,15800

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 5.6 km from Phillips County. 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 USC00054082 (Holyoke). Public domain.