Lincoln Frost Dates and Growing Season

NOAA 1991-2020 normals for Lincoln RS, 2.1 km from Lincoln, elevation 4575 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lincoln RS. 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 May 26, first September 11

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	Jun 15	Jun 6	Jun 1	May 29	May 26	May 22	May 19	May 15	May 11
24°F	May 25	May 20	May 15	May 12	May 10	May 7	May 4	May 1	Apr 26
20°F	May 12	May 8	May 4	May 1	Apr 28	Apr 25	Apr 20	Apr 16	Apr 11
16°F	May 4	Apr 28	Apr 22	Apr 17	Apr 13	Apr 8	Apr 3	Mar 29	Mar 19

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 25	Aug 30	Sep 3	Sep 7	Sep 11	Sep 15	Sep 19	Sep 23	Sep 30
24°F	Sep 9	Sep 16	Sep 21	Sep 25	Sep 29	Oct 1	Oct 4	Oct 9	Oct 15
20°F	Sep 23	Sep 29	Oct 2	Oct 5	Oct 10	Oct 14	Oct 18	Oct 22	Oct 28
16°F	Oct 1	Oct 7	Oct 12	Oct 18	Oct 23	Oct 26	Oct 31	Nov 3	Nov 10

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	54	45	39	35	31	28	25	21	18
32°F	93	83	76	71	65	60	54	48	39
28°F	131	122	115	110	105	100	94	88	80
24°F	161	154	149	145	140	135	130	122	114
20°F	190	182	176	171	166	161	156	151	142
16°F	224	212	205	198	192	186	180	172	162

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: 8,788
Cooling degree days, base 65°F: 70
Growing degree days, base 40°F: 2,711
Growing degree days, base 45°F: 1,843
Growing degree days, base 50°F: 1,147
Growing degree days, base 55°F: 621
Growing degree days, base 60°F: 264

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	1,333	0	0
February	1,119	0	0
March	998	0	0
April	759	0	6
May	532	1	62
June	288	6	186
July	114	38	390
August	138	24	355
September	367	1	129
October	730	0	17
November	1,067	0	0
December	1,344	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 2.1 km from Lincoln. 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 USC00245040 (Lincoln RS). Public domain.