Stratton climate

Stratton Frost Dates and Growing Season

NOAA 1991-2020 normals for Cripple Creek 3NNW, 6.9 km from Stratton, elevation 9235 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cripple Creek 3NNW. 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 26 and the first fall freeze around September 26, a growing season of about 121 days.

Median at 36°F
last June 6, first September 17
Median at 32°F
last May 26, first September 26
Median at 28°F
last May 14, first October 4

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 20Jun 15Jun 12Jun 9Jun 6Jun 4Jun 1May 30May 26
32°FJun 9Jun 4Jun 1May 30May 26May 24May 22May 19May 15
28°FMay 28May 23May 20May 17May 14May 12May 9May 7May 3
24°FMay 19May 14May 10May 8May 5May 3May 1Apr 28Apr 23
20°FMay 9May 4May 1Apr 29Apr 25Apr 22Apr 19Apr 15Apr 9
16°FMay 2Apr 26Apr 21Apr 18Apr 15Apr 11Apr 6Apr 2Mar 27

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 3Sep 7Sep 11Sep 15Sep 17Sep 20Sep 22Sep 24Sep 28
32°FSep 13Sep 17Sep 21Sep 24Sep 26Sep 28Oct 1Oct 3Oct 7
28°FSep 22Sep 26Sep 29Oct 2Oct 4Oct 6Oct 9Oct 13Oct 18
24°FOct 1Oct 4Oct 8Oct 11Oct 14Oct 17Oct 20Oct 23Oct 29
20°FOct 9Oct 14Oct 17Oct 20Oct 23Oct 27Oct 31Nov 3Nov 8
16°FOct 17Oct 21Oct 25Oct 29Nov 1Nov 3Nov 7Nov 12Nov 18

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°F11811210810410197939083
32°F138133128125121118113108102
28°F159153149145141138135130123
24°F178172167163160156153148142
20°F202195189185180176171167159
16°F225216209205199195190186176

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
8,533
Cooling degree days, base 65°F
28
Growing degree days, base 40°F
2,792
Growing degree days, base 45°F
1,904
Growing degree days, base 50°F
1,176
Growing degree days, base 55°F
594
Growing degree days, base 60°F
202

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26000
February1,11000
March1,02001
April82805
May567057
June2248248
July9916381
August1684303
September3321157
October693024
November97101
December1,26000

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 6.9 km from Stratton. 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 USC00051977 (Cripple Creek 3NNW). Public domain.