Loretto climate

Loretto Frost Dates and Growing Season

NOAA 1991-2020 normals for Ebensburg Sewage Plt, 9.4 km from Loretto, elevation 1940 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ebensburg Sewage Plt. 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 17 and the first fall freeze around October 2, a growing season of about 136 days.

Median at 36°F
last May 31, first September 22
Median at 32°F
last May 17, first October 2
Median at 28°F
last May 4, first October 13

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 14Jun 8Jun 4Jun 1May 31May 27May 24May 19May 13
32°FJun 1May 28May 25May 20May 17May 14May 10May 5Apr 30
28°FMay 22May 17May 12May 8May 4Apr 30Apr 27Apr 23Apr 18
24°FMay 12May 4Apr 30Apr 25Apr 21Apr 18Apr 15Apr 11Apr 5
20°FApr 25Apr 17Apr 14Apr 10Apr 7Apr 4Apr 1Mar 29Mar 23
16°FApr 8Apr 4Apr 1Mar 30Mar 27Mar 24Mar 20Mar 17Mar 11

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 5Sep 11Sep 15Sep 18Sep 22Sep 24Sep 27Oct 1Oct 3
32°FSep 19Sep 24Sep 27Sep 30Oct 2Oct 4Oct 6Oct 9Oct 14
28°FOct 1Oct 4Oct 6Oct 10Oct 13Oct 16Oct 20Oct 24Oct 30
24°FOct 11Oct 17Oct 21Oct 25Oct 29Nov 1Nov 3Nov 6Nov 13
20°FOct 27Nov 1Nov 3Nov 5Nov 8Nov 12Nov 15Nov 20Nov 25
16°FNov 4Nov 8Nov 12Nov 16Nov 18Nov 22Nov 27Dec 1Dec 6

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°F13412612111711210910410092
32°F159152146141136131126122114
28°F183175170165160157153146139
24°F210204198193188183178171164
20°F236229224220216212207201193
16°F261253247242237233229224217

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
6,963
Cooling degree days, base 65°F
294
Growing degree days, base 40°F
4,155
Growing degree days, base 45°F
3,073
Growing degree days, base 50°F
2,143
Growing degree days, base 55°F
1,358
Growing degree days, base 60°F
730

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26201
February1,08200
March952010
April572164
May30214216
June9957410
July35112542
August5182496
September18627302
October506287
November809013
December1,10802

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 9.4 km from Loretto. 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 USC00362470 (Ebensburg Sewage Plt). Public domain.