Phillips climate

Phillips Frost Dates and Growing Season

NOAA 1991-2020 normals for Prentice #2, 18.6 km from Phillips, elevation 1540 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Prentice #2. 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 23 and the first fall freeze around September 23, a growing season of about 124 days.

Median at 36°F
last June 2, first September 10
Median at 32°F
last May 23, first September 23
Median at 28°F
last May 9, first October 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°FJun 22Jun 14Jun 8Jun 5Jun 2May 31May 29May 25May 20
32°FJun 6Jun 1May 29May 26May 23May 19May 16May 12May 6
28°FMay 24May 19May 15May 12May 9May 5May 2Apr 29Apr 24
24°FMay 13May 7May 3Apr 30Apr 28Apr 25Apr 22Apr 17Apr 12
20°FMay 1Apr 27Apr 23Apr 20Apr 16Apr 14Apr 10Apr 7Apr 2
16°FApr 22Apr 17Apr 13Apr 10Apr 8Apr 5Apr 2Mar 31Mar 26

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°FAug 23Aug 31Sep 3Sep 7Sep 10Sep 14Sep 17Sep 20Sep 25
32°FSep 5Sep 12Sep 16Sep 20Sep 23Sep 26Sep 29Oct 2Oct 5
28°FSep 19Sep 24Sep 28Oct 1Oct 3Oct 5Oct 8Oct 12Oct 18
24°FSep 30Oct 4Oct 7Oct 10Oct 14Oct 17Oct 21Oct 26Oct 31
20°FOct 10Oct 15Oct 20Oct 24Oct 28Oct 31Nov 2Nov 5Nov 11
16°FOct 23Oct 29Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 21

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°F1201131081039893888170
32°F144137132128124119115109102
28°F167160155150146142136132125
24°F193184178174169165159154144
20°F213206201196192188183177169
16°F232225220216211207203197191

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
9,082
Cooling degree days, base 65°F
269
Growing degree days, base 40°F
3,574
Growing degree days, base 45°F
2,651
Growing degree days, base 50°F
1,848
Growing degree days, base 55°F
1,169
Growing degree days, base 60°F
637

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,67800
February1,41000
March1,18703
April734131
May37414175
June12459389
July54100512
August8270453
September27024233
October651149
November1,04403
December1,47400

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 18.6 km from Phillips. 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 USC00476859 (Prentice #2). Public domain.