Monument climate

Monument Frost Dates and Growing Season

NOAA 1991-2020 normals for Monument, 1.3 km from Monument, elevation 7080 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Monument. 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 14 and the first fall freeze around October 1, a growing season of about 138 days.

Median at 36°F
last May 27, first September 21
Median at 32°F
last May 14, first October 1
Median at 28°F
last May 3, first October 10

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 12Jun 6Jun 3May 31May 27May 24May 21May 18May 14
32°FMay 31May 24May 20May 17May 14May 11May 9May 6May 2
28°FMay 16May 11May 8May 5May 3May 1Apr 29Apr 26Apr 21
24°FMay 7May 3Apr 30Apr 28Apr 25Apr 21Apr 18Apr 15Apr 9
20°FApr 30Apr 25Apr 21Apr 18Apr 15Apr 11Apr 7Apr 4Mar 29
16°FApr 22Apr 16Apr 12Apr 8Apr 4Mar 31Mar 25Mar 21Mar 14

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 9Sep 13Sep 16Sep 19Sep 21Sep 23Sep 26Sep 30Oct 4
32°FSep 16Sep 21Sep 24Sep 28Oct 1Oct 3Oct 6Oct 9Oct 14
28°FSep 23Sep 30Oct 3Oct 7Oct 10Oct 13Oct 17Oct 20Oct 25
24°FOct 2Oct 9Oct 14Oct 17Oct 20Oct 23Oct 25Oct 29Nov 2
20°FOct 14Oct 19Oct 23Oct 26Oct 29Nov 1Nov 3Nov 7Nov 12
16°FOct 21Oct 27Nov 1Nov 3Nov 6Nov 9Nov 13Nov 17Nov 22

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°F13412812311911611210710296
32°F155150146141138134130125116
28°F176170166162158154150144137
24°F198191185181177174170165157
20°F220211206201197193189183175
16°F240232226221216211207201194

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
6,971
Cooling degree days, base 65°F
243
Growing degree days, base 40°F
3,876
Growing degree days, base 45°F
2,829
Growing degree days, base 50°F
1,953
Growing degree days, base 55°F
1,223
Growing degree days, base 60°F
644

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12800
February95800
March87904
April663030
May3704156
June10646393
July26122561
August4260484
September22311258
October563061
November88907
December1,12500

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 1.3 km from Monument. 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 USC00055734 (Monument). Public domain.