Rawlins climate

Rawlins Frost Dates and Growing Season

NOAA 1991-2020 normals for Rawlins 1N, 1.4 km from Rawlins, elevation 6908 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rawlins 1N. 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 May 17 and the first fall freeze around October 2, a growing season of about 138 days.

Median at 36°F
last May 31, first September 24
Median at 32°F
last May 17, first October 2
Median at 28°F
last May 6, first October 12

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°FJun 9Jun 5Jun 3Jun 1May 31May 27May 25May 22May 17
32°FMay 31May 26May 22May 20May 17May 15May 12May 9May 5
28°FMay 18May 14May 11May 9May 6May 3May 1Apr 28Apr 21
24°FMay 8May 4May 1Apr 28Apr 25Apr 21Apr 16Apr 11Apr 6
20°FApr 30Apr 23Apr 19Apr 14Apr 10Apr 6Apr 3Mar 31Mar 24
16°FApr 20Apr 13Apr 8Apr 4Mar 31Mar 28Mar 22Mar 17Mar 11

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°FSep 12Sep 15Sep 19Sep 22Sep 24Sep 26Sep 28Oct 1Oct 6
32°FSep 22Sep 25Sep 27Sep 30Oct 2Oct 4Oct 8Oct 11Oct 17
28°FSep 28Oct 2Oct 5Oct 9Oct 12Oct 15Oct 18Oct 21Oct 25
24°FOct 6Oct 10Oct 15Oct 18Oct 21Oct 24Oct 27Oct 30Nov 4
20°FOct 13Oct 18Oct 23Oct 26Oct 29Nov 1Nov 4Nov 9Nov 14
16°FOct 21Oct 27Oct 31Nov 3Nov 7Nov 10Nov 14Nov 18Nov 24

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°F13412912512211711411010599
32°F156150146142138134131125119
28°F176170165161158155150145137
24°F200193188183178174169164158
20°F225215209204199194189183174
16°F245236229223218213208201194

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
7,958
Cooling degree days, base 65°F
261
Growing degree days, base 40°F
3,639
Growing degree days, base 45°F
2,692
Growing degree days, base 50°F
1,883
Growing degree days, base 55°F
1,204
Growing degree days, base 60°F
654

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30500
February1,13700
March99202
April738015
May4602114
June14934341
July16123571
August4186510
September22015269
October628057
November97203
December1,30200

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 1.4 km from Rawlins. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00487529 (Rawlins 1N). Public domain.