Belmont climate

Belmont Frost Dates and Growing Season

NOAA 1991-2020 normals for Platteville, 10.8 km from Belmont, elevation 990 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Platteville. 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 30 and the first fall freeze around October 13, a growing season of about 166 days.

Median at 36°F
last May 8, first October 3
Median at 32°F
last April 30, first October 13
Median at 28°F
last April 17, 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 23May 18May 15May 11May 8May 5May 3Apr 30Apr 25
32°FMay 13May 8May 4May 1Apr 30Apr 27Apr 23Apr 19Apr 14
28°FMay 2Apr 28Apr 24Apr 20Apr 17Apr 14Apr 11Apr 7Apr 3
24°FApr 21Apr 15Apr 11Apr 8Apr 6Apr 3Apr 1Mar 29Mar 21
20°FApr 10Apr 5Apr 2Mar 31Mar 28Mar 25Mar 20Mar 16Mar 11
16°FApr 2Mar 29Mar 26Mar 22Mar 18Mar 15Mar 12Mar 8Mar 3

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 20Sep 24Sep 28Oct 1Oct 3Oct 5Oct 7Oct 10Oct 14
32°FSep 29Oct 4Oct 7Oct 10Oct 13Oct 15Oct 18Oct 20Oct 24
28°FOct 9Oct 14Oct 17Oct 20Oct 22Oct 25Oct 27Oct 30Nov 3
24°FOct 20Oct 25Oct 27Oct 30Nov 1Nov 3Nov 6Nov 11Nov 16
20°FNov 1Nov 4Nov 7Nov 10Nov 14Nov 16Nov 19Nov 23Nov 28
16°FNov 8Nov 13Nov 16Nov 19Nov 22Nov 25Nov 28Dec 1Dec 6

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°F165159154150146143140135129
32°F185178173169166161158153146
28°F206200195192187183179173167
24°F232223217213209205202196190
20°F252244239234230226221216209
16°F270263257253248244239234227

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
7,260
Cooling degree days, base 65°F
634
Growing degree days, base 40°F
4,689
Growing degree days, base 45°F
3,627
Growing degree days, base 50°F
2,688
Growing degree days, base 55°F
1,874
Growing degree days, base 60°F
1,186

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,46300
February1,19700
March960012
April565266
May25332269
June45142547
July8219676
August18171618
September14460373
October4828112
November861013
December1,26602

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 10.8 km from Belmont. 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 USC00476646 (Platteville). Public domain.