Normandy climate

Normandy Frost Dates and Growing Season

NOAA 1991-2020 normals for Neshaminy Falls, 6.2 km from Normandy, elevation 40 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Neshaminy Falls. 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 April 21 and the first fall freeze around October 25, a growing season of about 185 days.

Median at 36°F
last May 3, first October 13
Median at 32°F
last April 21, first October 25
Median at 28°F
last April 8, first November 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°FMay 22May 15May 10May 6May 3Apr 30Apr 28Apr 24Apr 19
32°FMay 7May 1Apr 27Apr 24Apr 21Apr 18Apr 15Apr 12Apr 6
28°FApr 21Apr 17Apr 14Apr 10Apr 8Apr 5Apr 2Mar 30Mar 24
24°FApr 12Apr 6Apr 3Apr 1Mar 29Mar 26Mar 22Mar 18Mar 12
20°FApr 2Mar 29Mar 25Mar 21Mar 17Mar 14Mar 10Mar 6Feb 26
16°FMar 25Mar 17Mar 13Mar 8Mar 5Mar 1Feb 26Feb 20Feb 12

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°FOct 1Oct 5Oct 8Oct 11Oct 13Oct 16Oct 19Oct 24Oct 29
32°FOct 11Oct 15Oct 18Oct 22Oct 25Oct 28Oct 30Nov 2Nov 5
28°FOct 20Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 16
24°FOct 30Nov 4Nov 8Nov 11Nov 14Nov 16Nov 21Nov 25Dec 1
20°FNov 11Nov 17Nov 21Nov 24Nov 28Dec 1Dec 5Dec 10Dec 18
16°FNov 25Dec 1Dec 6Dec 11Dec 17Dec 22Dec 27Jan 1Jan 9

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°F183176170166162158153148139
32°F205197193189185180176170162
28°F229223217213209205200196189
24°F254247241237232228224218210
20°F283274268261256252247241233
16°F309301295290285279274268259

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
5,340
Cooling degree days, base 65°F
966
Growing degree days, base 40°F
5,675
Growing degree days, base 45°F
4,437
Growing degree days, base 50°F
3,352
Growing degree days, base 55°F
2,416
Growing degree days, base 60°F
1,621

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07103
February91302
March777021
April4288118
May17548343
June25188614
July1326790
August3274736
September64110497
October33612183
November633036
December91608

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 6.2 km from Normandy. 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 USC00366194 (Neshaminy Falls). Public domain.