Brockway climate

Brockway Frost Dates and Growing Season

NOAA 1991-2020 normals for Dubois Jefferson CO AP, 11.5 km from Brockway, elevation 1814 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dubois Jefferson CO 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 May 6 and the first fall freeze around October 14, a growing season of about 160 days.

Median at 36°F
last May 18, first October 1
Median at 32°F
last May 6, first October 14
Median at 28°F
last April 24, first October 28

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

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 19Sep 23Sep 26Sep 29Oct 1Oct 4Oct 6Oct 10Oct 13
32°FSep 29Oct 3Oct 7Oct 11Oct 14Oct 17Oct 20Oct 25Nov 1
28°FOct 11Oct 17Oct 21Oct 25Oct 28Nov 1Nov 3Nov 7Nov 11
24°FOct 27Nov 1Nov 3Nov 7Nov 9Nov 12Nov 15Nov 20Nov 25
20°FNov 6Nov 10Nov 14Nov 16Nov 20Nov 24Nov 28Dec 1Dec 7
16°FNov 12Nov 17Nov 22Nov 27Dec 1Dec 4Dec 7Dec 12Dec 19

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°F158150146141137132128123116
32°F183175169164160156149145139
28°F208201196191186181177171162
24°F236229222217213208203197190
20°F258250244239235232227222215
16°F279269264259254249244238230

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
6,673
Cooling degree days, base 65°F
413
Growing degree days, base 40°F
4,506
Growing degree days, base 45°F
3,398
Growing degree days, base 50°F
2,428
Growing degree days, base 55°F
1,597
Growing degree days, base 60°F
915

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,25702
February1,07102
March926017
April539483
May26428257
June7477454
July20145591
August32117550
September15939337
October4685111
November774021
December1,09103

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 11.5 km from Brockway. 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 USW00004787 (Dubois Jefferson CO AP). Public domain.