Clearfield climate

Clearfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Clearfield Lawrence AP, 3.2 km from Clearfield, elevation 1516 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clearfield Lawrence AP. 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 4 and the first fall freeze around October 11, a growing season of about 161 days.

Median at 36°F
last May 17, first September 30
Median at 32°F
last May 4, first October 11
Median at 28°F
last April 23, first October 27

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 31May 27May 23May 20May 17May 12May 8May 4Apr 29
32°FMay 22May 16May 10May 7May 4Apr 30Apr 27Apr 24Apr 19
28°FMay 11May 4Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13Apr 8
24°FApr 27Apr 20Apr 16Apr 13Apr 10Apr 6Apr 3Apr 1Mar 26
20°FApr 13Apr 7Apr 3Apr 1Mar 30Mar 26Mar 23Mar 19Mar 13
16°FApr 1Mar 28Mar 25Mar 21Mar 18Mar 15Mar 12Mar 9Mar 3

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 17Sep 21Sep 24Sep 27Sep 30Oct 1Oct 4Oct 7Oct 12
32°FSep 29Oct 2Oct 5Oct 8Oct 11Oct 14Oct 17Oct 22Oct 29
28°FOct 11Oct 16Oct 21Oct 24Oct 27Oct 31Nov 2Nov 5Nov 9
24°FOct 24Oct 30Nov 2Nov 4Nov 8Nov 10Nov 13Nov 16Nov 21
20°FNov 5Nov 10Nov 13Nov 15Nov 18Nov 21Nov 25Nov 30Dec 5
16°FNov 13Nov 18Nov 22Nov 27Dec 1Dec 4Dec 7Dec 12Dec 18

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°F157151146141136132127123115
32°F183176171166161156151146136
28°F208201196192187183178172165
24°F233225220215211207203198191
20°F256249244240236231228222215
16°F281273267262258252248243236

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
6,391
Cooling degree days, base 65°F
491
Growing degree days, base 40°F
4,675
Growing degree days, base 45°F
3,551
Growing degree days, base 50°F
2,568
Growing degree days, base 55°F
1,721
Growing degree days, base 60°F
1,023

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22001
February1,02302
March885016
April516384
May23628275
June5792485
July12179632
August21140584
September14544354
October4475116
November758017
December1,07302

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 3.2 km from Clearfield. 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 USW00054792 (Clearfield Lawrence AP). Public domain.