Monte Vista climate

Monte Vista Frost Dates and Growing Season

NOAA 1991-2020 normals for Monte Vista 2W, 3.4 km from Monte Vista, elevation 7695 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Monte Vista 2W. 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 11 and the first fall freeze around September 13, a growing season of about 92 days.

Median at 32°F
last June 11, first September 13
Median at 28°F
last May 30, 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 25Jun 20Jun 17Jun 14Jun 11Jun 9Jun 6Jun 4Jun 1
28°FJun 12Jun 7Jun 4Jun 1May 30May 27May 23May 19May 15
24°FMay 29May 23May 20May 17May 15May 11May 8May 5May 1
20°FMay 15May 10May 6May 4May 1Apr 30Apr 27Apr 23Apr 19
16°FMay 4Apr 30Apr 27Apr 24Apr 21Apr 19Apr 16Apr 13Apr 8

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°FSep 1Sep 5Sep 7Sep 11Sep 13Sep 15Sep 17Sep 20Sep 24
28°FSep 11Sep 15Sep 18Sep 21Sep 23Sep 26Sep 28Oct 1Oct 4
24°FSep 19Sep 23Sep 26Sep 28Sep 30Oct 2Oct 5Oct 8Oct 12
20°FSep 27Oct 1Oct 4Oct 6Oct 9Oct 11Oct 14Oct 18Oct 22
16°FOct 3Oct 8Oct 11Oct 15Oct 18Oct 20Oct 23Oct 27Nov 1

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°F807570666258544739
32°F10810299959289858174
28°F13312812311911511210810398
24°F156150146142139136133129121
20°F176171167164160156153148142
16°F197190186181178174170165159

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
8,950
Cooling degree days, base 65°F
15
Growing degree days, base 40°F
2,832
Growing degree days, base 45°F
1,920
Growing degree days, base 50°F
1,170
Growing degree days, base 55°F
579
Growing degree days, base 60°F
178

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,53600
February1,19600
March97200
April73505
May488070
June2192238
July8810387
August1413327
September3410135
October70109
November1,05300
December1,48200

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 3.4 km from Monte Vista. 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 USC00055706 (Monte Vista 2W). Public domain.