Summit Park climate

Summit Park Frost Dates and Growing Season

NOAA 1991-2020 normals for Mtn Dell Dam, 9.4 km from Summit Park, elevation 5420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mtn Dell Dam. 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 7 and the first fall freeze around October 14, a growing season of about 158 days.

Median at 36°F
last May 25, first October 1
Median at 32°F
last May 7, first October 14
Median at 28°F
last April 21, first October 26

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 11Jun 6Jun 1May 29May 25May 21May 16May 13May 8
32°FMay 27May 17May 13May 9May 7May 4May 1Apr 27Apr 21
28°FMay 6May 2Apr 28Apr 25Apr 21Apr 17Apr 13Apr 9Apr 4
24°FApr 21Apr 15Apr 12Apr 8Apr 5Apr 2Mar 29Mar 22Mar 14
20°FApr 11Apr 4Mar 31Mar 26Mar 20Mar 14Mar 10Mar 5Feb 28
16°FMar 27Mar 18Mar 12Mar 8Mar 4Feb 28Feb 25Feb 21Feb 15

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 15Sep 20Sep 24Sep 28Oct 1Oct 2Oct 6Oct 10Oct 15
32°FSep 29Oct 3Oct 6Oct 11Oct 14Oct 16Oct 20Oct 23Oct 27
28°FOct 11Oct 16Oct 19Oct 23Oct 26Oct 28Nov 1Nov 4Nov 9
24°FOct 22Oct 27Oct 31Nov 3Nov 6Nov 9Nov 12Nov 16Nov 21
20°FNov 1Nov 5Nov 10Nov 13Nov 17Nov 20Nov 23Nov 26Dec 1
16°FNov 8Nov 15Nov 19Nov 22Nov 25Nov 28Dec 1Dec 5Dec 11

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°F150143137132128123118112104
32°F180172167162158153147141133
28°F209202196192188183178173166
24°F237229223217213209204199193
20°F266257250244239234228221214
16°F291281275269265260254247237

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
5,904
Cooling degree days, base 65°F
617
Growing degree days, base 40°F
4,874
Growing degree days, base 45°F
3,687
Growing degree days, base 50°F
2,678
Growing degree days, base 55°F
1,842
Growing degree days, base 60°F
1,158

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08000
February87101
March718015
April515061
May27311227
June8483451
July3249711
August6218677
September10955402
October4241119
November755013
December1,06600

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 9.4 km from Summit Park. 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 USC00425892 (Mtn Dell Dam). Public domain.