Marbleton Frost Dates and Growing Season

NOAA 1991-2020 normals for Big Piney Marbleton AP, 3.4 km from Marbleton, elevation 6970 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Big Piney Marbleton AP. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

NOAA does not state freeze dates for this station.

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	–	–	–	–	–	–	–	–	–
32°F	–	–	–	–	–	–	–	–	–
28°F	–	–	–	–	–	–	–	–	–
24°F	Jun 17	Jun 10	Jun 6	Jun 2	May 29	May 24	May 20	May 16	May 11
20°F	May 31	May 24	May 19	May 15	May 12	May 9	May 6	May 3	Apr 29
16°F	May 17	May 10	May 5	May 2	Apr 30	Apr 27	Apr 24	Apr 20	Apr 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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	–	–	–	–	–	–	–	–	–
32°F	–	–	–	–	–	–	–	–	–
28°F	–	–	–	–	–	–	–	–	–
24°F	Sep 1	Sep 6	Sep 10	Sep 14	Sep 17	Sep 19	Sep 22	Sep 26	Oct 1
20°F	Sep 15	Sep 20	Sep 24	Sep 28	Sep 30	Oct 3	Oct 6	Oct 10	Oct 14
16°F	Sep 27	Oct 2	Oct 5	Oct 8	Oct 12	Oct 14	Oct 17	Oct 20	Oct 25

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	46	39	35	31	28	24	21	18	15
32°F	76	68	62	57	52	47	42	37	30
28°F	104	97	92	87	82	77	73	66	56
24°F	133	125	120	115	111	106	100	94	85
20°F	160	152	147	142	138	134	129	123	114
16°F	184	178	173	168	164	160	155	149	142

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: 10,404
Cooling degree days, base 65°F: 31
Growing degree days, base 40°F: 2,371
Growing degree days, base 45°F: 1,605
Growing degree days, base 50°F: 980
Growing degree days, base 55°F: 491
Growing degree days, base 60°F: 170

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	1,652	0	0
February	1,403	0	0
March	1,181	0	0
April	860	0	1
May	609	0	35
June	325	1	160
July	112	17	371
August	164	12	316
September	428	0	93
October	831	0	5
November	1,218	0	0
December	1,621	0	0

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 Marbleton. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00024164 (Big Piney Marbleton AP). Public domain.