Belt climate

Belt Frost Dates and Growing Season

NOAA 1991-2020 normals for Raynesford 2 Nnw, 16.7 km from Belt, elevation 4215 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Raynesford 2 Nnw. 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 22 and the first fall freeze around September 23, a growing season of about 123 days.

Median at 36°F
last June 9, first September 12
Median at 32°F
last May 22, first September 23
Median at 28°F
last May 7, first October 2

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

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°FAug 27Sep 2Sep 5Sep 9Sep 12Sep 15Sep 18Sep 21Sep 25
32°FSep 7Sep 13Sep 17Sep 21Sep 23Sep 26Sep 29Oct 2Oct 6
28°FSep 20Sep 24Sep 27Sep 30Oct 2Oct 5Oct 8Oct 12Oct 18
24°FSep 27Oct 1Oct 5Oct 9Oct 11Oct 15Oct 18Oct 23Oct 29
20°FOct 1Oct 7Oct 12Oct 16Oct 19Oct 23Oct 28Nov 1Nov 8
16°FOct 10Oct 17Oct 21Oct 26Oct 29Nov 2Nov 5Nov 10Nov 16

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°F114107101969288827563
32°F14413713212712311811310799
28°F169161156152147143140135128
24°F193184178172168163159154146
20°F215206200194188182177170162
16°F232224218212207201195188179

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
7,580
Cooling degree days, base 65°F
280
Growing degree days, base 40°F
3,689
Growing degree days, base 45°F
2,657
Growing degree days, base 50°F
1,804
Growing degree days, base 55°F
1,125
Growing degree days, base 60°F
621

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,19001
February1,05601
March94208
April669030
May4343117
June21316263
July59116523
August62115520
September24428262
October615168
November918011
December1,17801

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 16.7 km from Belt. 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 USC00246902 (Raynesford 2 Nnw). Public domain.