Allenspark climate

Allenspark Frost Dates and Growing Season

NOAA 1991-2020 normals for Estes Park 3 Sse, 17.2 km from Allenspark, elevation 7812 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Estes Park 3 Sse. 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 30 and the first fall freeze around September 17, a growing season of about 109 days.

Median at 36°F
last June 12, first September 6
Median at 32°F
last May 30, first September 17
Median at 28°F
last May 16, first September 28

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 28Jun 22Jun 18Jun 15Jun 12Jun 9Jun 6Jun 2May 29
32°FJun 14Jun 8Jun 4Jun 1May 30May 26May 24May 20May 15
28°FMay 31May 25May 21May 18May 16May 12May 9May 7May 3
24°FMay 18May 13May 9May 6May 4May 2Apr 30Apr 26Apr 21
20°FMay 9May 4May 1Apr 28Apr 25Apr 21Apr 18Apr 14Apr 9
16°FMay 1Apr 26Apr 22Apr 17Apr 13Apr 9Apr 6Apr 3Mar 29

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 23Aug 29Sep 1Sep 4Sep 6Sep 9Sep 12Sep 16Sep 20
32°FSep 3Sep 7Sep 11Sep 14Sep 17Sep 20Sep 23Sep 26Oct 1
28°FSep 12Sep 17Sep 21Sep 25Sep 28Sep 30Oct 3Oct 7Oct 12
24°FSep 23Sep 29Oct 1Oct 5Oct 8Oct 11Oct 15Oct 18Oct 24
20°FOct 2Oct 6Oct 11Oct 14Oct 18Oct 22Oct 26Oct 31Nov 5
16°FOct 10Oct 15Oct 20Oct 25Oct 30Nov 1Nov 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°F1059993898480757062
32°F1301231171131091051019587
28°F154147143139134130124119112
24°F174168163159155151147142134
20°F199191185179175171166160152
16°F222212205199195190185179171

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
8,095
Cooling degree days, base 65°F
85
Growing degree days, base 40°F
3,059
Growing degree days, base 45°F
2,132
Growing degree days, base 50°F
1,377
Growing degree days, base 55°F
776
Growing degree days, base 60°F
337

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,19100
February1,07400
March98902
April78609
May529179
June21714261
July6944440
August11523375
September3213174
October670034
November93603
December1,20000

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 17.2 km from Allenspark. 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 USC00052761 (Estes Park 3 Sse). Public domain.