Hinsdale County climate

Hinsdale County Frost Dates and Growing Season

NOAA 1991-2020 normals for Rio Grande Rsvr, 11.4 km from Hinsdale County, elevation 9493 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rio Grande Rsvr. 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 June 15 and the first fall freeze around September 11, a growing season of about 85 days.

Median at 32°F
last June 15, first September 11
Median at 28°F
last May 31, first September 23

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°F–––––––––
32°FJun 30Jun 25Jun 21Jun 18Jun 15Jun 12Jun 10Jun 6Jun 2
28°FJun 16Jun 9Jun 5Jun 2May 31May 26May 23May 19May 14
24°FJun 1May 23May 19May 15May 12May 10May 8May 5May 3
20°FMay 16May 11May 7May 5May 3May 2Apr 30Apr 27Apr 21
16°FMay 7May 3Apr 30Apr 28Apr 25Apr 22Apr 19Apr 15Apr 10

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°F–––––––––
32°FAug 27Sep 1Sep 5Sep 8Sep 11Sep 13Sep 16Sep 19Sep 23
28°FSep 11Sep 15Sep 18Sep 21Sep 23Sep 26Sep 28Oct 1Oct 5
24°FSep 20Sep 26Sep 29Oct 1Oct 3Oct 6Oct 9Oct 12Oct 16
20°FSep 30Oct 4Oct 7Oct 10Oct 13Oct 16Oct 18Oct 21Oct 25
16°FOct 9Oct 14Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 5

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°F736762575347423729
32°F1049792888581777366
28°F13512712311911511110710194
24°F160154150146142138134128120
20°F179173169166162159155151144
16°F198192188184180177172167161

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
10,202
Cooling degree days, base 65°F
1
Growing degree days, base 40°F
2,193
Growing degree days, base 45°F
1,377
Growing degree days, base 50°F
729
Growing degree days, base 55°F
268
Growing degree days, base 60°F
40

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,54400
February1,33700
March1,21700
April90600
May629015
June3470128
July1871280
August2470221
September411080
October72906
November1,11500
December1,53600

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 Hinsdale County. 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 USC00057050 (Rio Grande Rsvr). Public domain.