Scottsbluff climate

Scottsbluff Frost Dates and Growing Season

NOAA 1991-2020 normals for Scottsbluff 1E, 2.3 km from Scottsbluff, elevation 3909 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Scottsbluff 1E. 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 8 and the first fall freeze around October 3, a growing season of about 147 days.

Median at 36°F
last May 18, first September 24
Median at 32°F
last May 8, first October 3
Median at 28°F
last April 28, 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°FMay 31May 27May 23May 20May 18May 16May 13May 10May 6
32°FMay 21May 16May 13May 11May 8May 5May 2Apr 30Apr 25
28°FMay 11May 6May 3Apr 30Apr 28Apr 25Apr 21Apr 17Apr 13
24°FMay 1Apr 26Apr 21Apr 18Apr 14Apr 11Apr 8Apr 4Mar 30
20°FApr 20Apr 14Apr 9Apr 6Apr 2Mar 31Mar 27Mar 22Mar 15
16°FApr 11Apr 4Mar 31Mar 28Mar 24Mar 19Mar 14Mar 9Mar 5

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

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°F146141136132128125121116110
32°F166159154151147143139135128
28°F185179174170166163158154147
24°F209201196192188184180175168
20°F230222217212208203198193186
16°F251244237232227222218211204

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
6,519
Cooling degree days, base 65°F
747
Growing degree days, base 40°F
4,850
Growing degree days, base 45°F
3,730
Growing degree days, base 50°F
2,773
Growing degree days, base 55°F
1,966
Growing degree days, base 60°F
1,291

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14900
February98502
March816018
April547166
May29722234
June58128521
July6291750
August16236685
September14068390
October507299
November84208
December1,15701

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 2.3 km from Scottsbluff. 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 USC00257667 (Scottsbluff 1E). Public domain.