Casco climate

Casco Frost Dates and Growing Season

NOAA 1991-2020 normals for Poland, 12.9 km from Casco, elevation 570 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Poland. 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 3 and the first fall freeze around October 7, a growing season of about 157 days.

Median at 36°F
last May 15, first September 29
Median at 32°F
last May 3, first October 7
Median at 28°F
last April 21, first October 22

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 28May 24May 20May 17May 15May 12May 9May 7May 3
32°FMay 16May 11May 8May 5May 3May 1Apr 29Apr 26Apr 23
28°FMay 1Apr 28Apr 25Apr 23Apr 21Apr 19Apr 17Apr 13Apr 10
24°FApr 21Apr 18Apr 15Apr 12Apr 10Apr 8Apr 6Apr 4Apr 1
20°FApr 12Apr 8Apr 6Apr 4Apr 2Apr 1Mar 31Mar 26Mar 20
16°FApr 4Apr 2Mar 31Mar 28Mar 24Mar 21Mar 19Mar 16Mar 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°FSep 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 2Oct 5Oct 9
32°FSep 27Sep 30Oct 2Oct 4Oct 7Oct 10Oct 13Oct 17Oct 23
28°FOct 5Oct 10Oct 15Oct 19Oct 22Oct 25Oct 29Nov 1Nov 5
24°FOct 20Oct 27Oct 31Nov 2Nov 4Nov 7Nov 10Nov 14Nov 18
20°FNov 3Nov 7Nov 11Nov 13Nov 17Nov 19Nov 21Nov 25Nov 29
16°FNov 13Nov 17Nov 21Nov 24Nov 26Nov 29Dec 1Dec 4Dec 10

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°F151146142138135132129124118
32°F176169164160157153150145139
28°F202196191187183179175170164
24°F224218214210207203200195188
20°F245239234231228224221216211
16°F266258254250246243238234228

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
7,893
Cooling degree days, base 65°F
316
Growing degree days, base 40°F
3,790
Growing degree days, base 45°F
2,819
Growing degree days, base 50°F
1,979
Growing degree days, base 55°F
1,274
Growing degree days, base 60°F
714

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,42600
February1,22400
March1,10503
April700126
May3739153
June12652380
July28129566
August4299522
September21826270
October568154
November87306
December1,21200

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 12.9 km from Casco. 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 USC00176856 (Poland). Public domain.