Brocton climate

Brocton Frost Dates and Growing Season

NOAA 1991-2020 normals for Portland1 Sw, 4.2 km from Brocton, elevation 808 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Portland1 Sw. 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 25 and the first fall freeze around October 31, a growing season of about 187 days.

Median at 36°F
last May 5, first October 17
Median at 32°F
last April 25, first October 31
Median at 28°F
last April 13, first November 12

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

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 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 27Nov 1
32°FOct 15Oct 20Oct 24Oct 28Oct 31Nov 3Nov 6Nov 9Nov 15
28°FOct 29Nov 3Nov 6Nov 9Nov 12Nov 15Nov 20Nov 24Nov 28
24°FNov 8Nov 14Nov 18Nov 22Nov 24Nov 27Dec 1Dec 4Dec 9
20°FNov 18Nov 23Nov 28Dec 1Dec 3Dec 6Dec 9Dec 14Dec 20
16°FNov 26Dec 1Dec 5Dec 8Dec 12Dec 17Dec 20Dec 24Jan 1

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°F185178173168163159155149142
32°F209202196191187183178173165
28°F234227221216213208204199190
24°F257249243239235232227222217
20°F276270265260256251246241234
16°F294287282278273269264259251

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
6,030
Cooling degree days, base 65°F
667
Growing degree days, base 40°F
5,114
Growing degree days, base 45°F
3,944
Growing degree days, base 50°F
2,924
Growing degree days, base 55°F
2,031
Growing degree days, base 60°F
1,273

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16901
February1,04702
March918021
April540379
May24035289
June37128542
July4214676
August9192648
September8683447
October34811177
November651041
December98303

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 4.2 km from Brocton. 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 USC00306747 (Portland1 Sw). Public domain.