Summerside climate

Summerside Frost Dates and Growing Season

NOAA 1991-2020 normals for Cincinnati Lunken AP, 11.3 km from Summerside, elevation 490 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cincinnati Lunken 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 April 16 and the first fall freeze around October 25, a growing season of about 190 days.

Median at 36°F
last April 29, first October 14
Median at 32°F
last April 16, first October 25
Median at 28°F
last April 2, first November 4

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 14May 9May 5May 1Apr 29Apr 25Apr 21Apr 18Apr 14
32°FMay 3Apr 27Apr 23Apr 19Apr 16Apr 14Apr 10Apr 6Apr 2
28°FApr 18Apr 13Apr 8Apr 5Apr 2Mar 31Mar 29Mar 25Mar 19
24°FApr 5Mar 31Mar 28Mar 25Mar 22Mar 19Mar 15Mar 11Mar 4
20°FMar 26Mar 21Mar 17Mar 14Mar 10Mar 6Mar 2Feb 27Feb 20
16°FMar 18Mar 12Mar 6Mar 2Feb 28Feb 23Feb 18Feb 9Feb 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°FOct 2Oct 6Oct 9Oct 12Oct 14Oct 16Oct 19Oct 22Oct 27
32°FOct 12Oct 16Oct 20Oct 22Oct 25Oct 28Oct 30Nov 1Nov 5
28°FOct 24Oct 29Nov 1Nov 2Nov 4Nov 6Nov 9Nov 13Nov 18
24°FNov 3Nov 6Nov 10Nov 12Nov 15Nov 18Nov 21Nov 26Dec 1
20°FNov 10Nov 15Nov 19Nov 23Nov 28Dec 1Dec 5Dec 9Dec 18
16°FNov 21Nov 28Dec 1Dec 6Dec 10Dec 16Dec 21Dec 26Jan 2

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°F186180176172168164159154147
32°F210203198194190185181177168
28°F235228223219215211207201193
24°F265255249244239235231226219
20°F292281275269264259253248239
16°F319309301296291286279272263

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
4,804
Cooling degree days, base 65°F
1,125
Growing degree days, base 40°F
6,247
Growing degree days, base 45°F
4,931
Growing degree days, base 50°F
3,763
Growing degree days, base 55°F
2,737
Growing degree days, base 60°F
1,859

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02008
February830011
March653256
April32612190
May11384438
June12229667
July1340804
August2305769
September52136534
October29518221
November612050
December890013

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 11.3 km from Summerside. 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 USW00093812 (Cincinnati Lunken AP). Public domain.