Fraser Frost Dates and Growing Season

NOAA 1991-2020 normals for Fraser, 0.3 km from Fraser, elevation 8560 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fraser. 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 21	Jun 13	Jun 8	Jun 5	Jun 2	May 30	May 26	May 23	May 17
20°F	May 28	May 23	May 19	May 15	May 12	May 9	May 6	May 3	Apr 30
16°F	May 15	May 10	May 6	May 3	May 1	Apr 29	Apr 26	Apr 22	Apr 17

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 3	Sep 6	Sep 9	Sep 11	Sep 14	Sep 16	Sep 18	Sep 21	Sep 26
20°F	Sep 11	Sep 16	Sep 19	Sep 22	Sep 24	Sep 27	Sep 30	Oct 3	Oct 7
16°F	Sep 20	Sep 25	Sep 29	Oct 2	Oct 5	Oct 9	Oct 13	Oct 16	Oct 21

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	24	20	16	14	13	11	10	8	6
32°F	55	46	40	36	32	29	25	21	16
28°F	89	82	77	73	69	64	59	52	43
24°F	123	115	111	107	103	99	94	89	81
20°F	152	145	141	137	132	128	124	119	112
16°F	178	170	165	161	157	153	149	142	136

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: 10,536
Cooling degree days, base 65°F: 0
Growing degree days, base 40°F: 1,924
Growing degree days, base 45°F: 1,156
Growing degree days, base 50°F: 566
Growing degree days, base 55°F: 174
Growing degree days, base 60°F: 19

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Growing DD 50
January	1,552	0
February	1,310	0
March	1,187	0
April	887	0
May	636	13
June	375	101
July	236	231
August	290	179
September	494	41
October	828	1
November	1,191	0
December	1,551	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 0.3 km from Fraser. 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 USC00053116 (Fraser). Public domain.