Chalmers climate

Chalmers Frost Dates and Growing Season

NOAA 1991-2020 normals for Chalmers 5 W, 7.3 km from Chalmers, elevation 720 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chalmers 5 W. 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 17, a growing season of about 173 days.

Median at 36°F
last May 5, first October 6
Median at 32°F
last April 25, first October 17
Median at 28°F
last April 12, 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°FMay 22May 16May 12May 8May 5May 2Apr 30Apr 27Apr 23
32°FMay 11May 5Apr 30Apr 28Apr 25Apr 22Apr 19Apr 16Apr 11
28°FApr 28Apr 23Apr 19Apr 16Apr 12Apr 9Apr 7Apr 4Apr 1
24°FApr 16Apr 10Apr 6Apr 4Apr 2Mar 31Mar 27Mar 22Mar 14
20°FApr 5Apr 1Mar 29Mar 25Mar 20Mar 17Mar 14Mar 9Mar 5
16°FMar 28Mar 21Mar 16Mar 13Mar 10Mar 7Mar 4Feb 28Feb 20

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 23Sep 28Sep 30Oct 3Oct 6Oct 9Oct 12Oct 15Oct 20
32°FOct 1Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Oct 29
28°FOct 12Oct 19Oct 23Oct 25Oct 28Oct 30Nov 1Nov 5Nov 10
24°FOct 27Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 23
20°FNov 4Nov 8Nov 12Nov 15Nov 19Nov 23Nov 26Dec 1Dec 6
16°FNov 11Nov 17Nov 23Nov 27Nov 30Dec 2Dec 6Dec 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°F171165159155151148144138132
32°F193187181177173170166161153
28°F216210205201197193189183176
24°F240234228223219215211207201
20°F267259253247241237233227220
16°F288279273267263258254247239

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
6,218
Cooling degree days, base 65°F
757
Growing degree days, base 40°F
5,227
Growing degree days, base 45°F
4,073
Growing degree days, base 50°F
3,050
Growing degree days, base 55°F
2,153
Growing degree days, base 60°F
1,387

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28000
February1,05802
March843230
April4724104
May19155345
June18169602
July9237693
August12189642
September10188438
October38713165
November743028
December1,10402

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 7.3 km from Chalmers. 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 USC00121417 (Chalmers 5 W). Public domain.