Lewis Run climate

Lewis Run Frost Dates and Growing Season

NOAA 1991-2020 normals for Bradford 4SW Rsch 5, 5.4 km from Lewis Run, elevation 1660 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bradford 4SW Rsch 5. 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 4, a growing season of about 140 days.

Median at 36°F
last May 29, first September 24
Median at 32°F
last May 18, first October 4
Median at 28°F
last May 4, first October 17

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 11Jun 6Jun 3May 31May 29May 26May 24May 21May 14
32°FMay 31May 27May 24May 21May 18May 15May 11May 6Apr 30
28°FMay 23May 17May 12May 8May 4Apr 30Apr 28Apr 25Apr 20
24°FMay 9May 4Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13Apr 8
20°FApr 25Apr 18Apr 15Apr 11Apr 8Apr 6Apr 3Apr 2Mar 29
16°FApr 11Apr 6Apr 3Apr 1Mar 31Mar 28Mar 24Mar 21Mar 16

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 10Sep 16Sep 19Sep 22Sep 24Sep 27Sep 29Oct 2Oct 6
32°FSep 21Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 14Oct 19
28°FOct 1Oct 7Oct 11Oct 14Oct 17Oct 21Oct 24Oct 28Nov 2
24°FOct 14Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 14
20°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 21Nov 27
16°FNov 6Nov 10Nov 14Nov 18Nov 21Nov 25Nov 29Dec 2Dec 8

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°F13613012612211811410910498
32°F161154149144140136132127122
28°F185179174169164159156150142
24°F210203198193189185180174167
20°F236228223219215211206201194
16°F258249244240236232227223217

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
7,459
Cooling degree days, base 65°F
292
Growing degree days, base 40°F
3,978
Growing degree days, base 45°F
2,948
Growing degree days, base 50°F
2,058
Growing degree days, base 55°F
1,304
Growing degree days, base 60°F
705

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,34101
February1,17200
March1,04007
April636150
May32518209
June10758405
July43108530
August5779487
September20526284
October537275
November836010
December1,16201

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 5.4 km from Lewis Run. 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 USC00360868 (Bradford 4SW Rsch 5). Public domain.