Star Valley Ranch Frost Dates and Growing Season

NOAA 1991-2020 normals for Bedford 3 Se, 11.6 km from Star Valley Ranch, elevation 6355 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bedford 3 Se. 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.

Median at 28°F: last June 3, first September 13

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	Jul 1	Jun 23	Jun 16	Jun 10	Jun 3	May 29	May 22	May 16	May 10
24°F	Jun 13	May 26	May 18	May 12	May 9	May 6	May 3	Apr 30	Apr 25
20°F	May 12	May 7	May 3	Apr 30	Apr 27	Apr 24	Apr 21	Apr 18	Apr 12
16°F	May 1	Apr 27	Apr 23	Apr 20	Apr 17	Apr 14	Apr 10	Apr 7	Apr 3

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	Aug 29	Sep 2	Sep 5	Sep 9	Sep 13	Sep 17	Sep 21	Sep 25	Oct 1
24°F	Sep 9	Sep 17	Sep 22	Sep 26	Sep 29	Oct 2	Oct 6	Oct 11	Oct 16
20°F	Sep 24	Oct 1	Oct 4	Oct 7	Oct 12	Oct 15	Oct 18	Oct 23	Oct 28
16°F	Oct 5	Oct 13	Oct 17	Oct 21	Oct 24	Oct 27	Oct 30	Nov 2	Nov 6

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	61	52	47	43	39	34	31	26	21
32°F	90	83	77	72	67	61	56	50	41
28°F	130	120	113	106	99	93	86	79	67
24°F	163	156	150	144	139	133	126	117	107
20°F	189	182	176	171	167	161	157	151	140
16°F	210	202	198	193	188	184	180	174	165

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: 9,615
Cooling degree days, base 65°F: 28
Growing degree days, base 40°F: 2,497
Growing degree days, base 45°F: 1,686
Growing degree days, base 50°F: 1,027
Growing degree days, base 55°F: 517
Growing degree days, base 60°F: 178

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	1,477	0	0
February	1,256	0	0
March	1,127	0	0
April	857	0	3
May	574	0	45
June	337	1	152
July	125	18	360
August	154	8	323
September	380	1	129
October	749	0	13
November	1,109	0	0
December	1,472	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 11.6 km from Star Valley Ranch. 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 USC00480603 (Bedford 3 Se). Public domain.