Bruce climate

Bruce Frost Dates and Growing Season

NOAA 1991-2020 normals for Weyerhaeuser 1N, 11.4 km from Bruce, elevation 1195 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Weyerhaeuser 1N. 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 9 and the first fall freeze around September 29, a growing season of about 140 days.

Median at 36°F
last May 22, first September 21
Median at 32°F
last May 9, first September 29
Median at 28°F
last April 28, first October 10

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 6Jun 1May 29May 25May 22May 19May 16May 12May 7
32°FMay 27May 21May 16May 12May 9May 6May 3Apr 30Apr 26
28°FMay 15May 8May 3Apr 30Apr 28Apr 25Apr 22Apr 18Apr 12
24°FMay 1Apr 26Apr 22Apr 19Apr 16Apr 13Apr 9Apr 6Apr 2
20°FApr 21Apr 16Apr 11Apr 8Apr 5Apr 3Apr 1Mar 30Mar 24
16°FApr 13Apr 8Apr 4Apr 2Mar 31Mar 28Mar 25Mar 22Mar 16

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 7Sep 12Sep 16Sep 18Sep 21Sep 23Sep 26Sep 30Oct 3
32°FSep 14Sep 20Sep 23Sep 26Sep 29Oct 1Oct 4Oct 8Oct 14
28°FSep 24Sep 30Oct 3Oct 6Oct 10Oct 13Oct 18Oct 22Oct 26
24°FOct 5Oct 13Oct 19Oct 22Oct 25Oct 28Oct 31Nov 3Nov 8
20°FOct 21Oct 28Oct 31Nov 2Nov 5Nov 7Nov 10Nov 13Nov 18
16°FOct 29Nov 2Nov 6Nov 9Nov 12Nov 14Nov 17Nov 21Nov 26

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°F139133129125120117112108101
32°F160153149145140136131125119
28°F186179174170165160155149142
24°F212205199195191186182176166
20°F230224219215212208204199192
16°F245237233230226223219214207

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
8,213
Cooling degree days, base 65°F
389
Growing degree days, base 40°F
4,069
Growing degree days, base 45°F
3,076
Growing degree days, base 50°F
2,205
Growing degree days, base 55°F
1,458
Growing degree days, base 60°F
844

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,58100
February1,31200
March1,06605
April630243
May29716219
June8680445
July23151593
August43103525
September20136298
October573171
November98804
December1,41300

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 11.4 km from Bruce. 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 USC00479144 (Weyerhaeuser 1N). Public domain.