Alliance climate

Alliance Frost Dates and Growing Season

NOAA 1991-2020 normals for Bayboro 3 Sw, 2 km from Alliance, elevation 5 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bayboro 3 Sw. 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 March 30 and the first fall freeze around November 8, a growing season of about 224 days.

Median at 36°F
last April 11, first October 31
Median at 32°F
last March 30, first November 8
Median at 28°F
last March 17, first November 20

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°FApr 25Apr 20Apr 17Apr 14Apr 11Apr 7Apr 2Mar 30Mar 25
32°FApr 15Apr 9Apr 5Apr 1Mar 30Mar 26Mar 23Mar 18Mar 11
28°FApr 4Mar 30Mar 25Mar 21Mar 17Mar 12Mar 6Feb 28Feb 22
24°FMar 24Mar 17Mar 10Mar 4Mar 1Feb 25Feb 19Feb 9Jan 30
20°FMar 9Mar 1Feb 24Feb 18Feb 10Feb 3Jan 30Jan 19Jan 7
16°FFeb 27Feb 16Feb 6Feb 1Jan 29Jan 24Jan 14Jan 4Dec 25

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°FOct 17Oct 22Oct 25Oct 28Oct 31Nov 1Nov 4Nov 7Nov 14
32°FOct 26Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15Nov 21Nov 30
28°FNov 3Nov 7Nov 11Nov 16Nov 20Nov 26Dec 1Dec 6Dec 20
24°FNov 14Nov 21Nov 28Dec 1Dec 6Dec 12Dec 23Jan 2Jan 12
20°FNov 30Dec 6Dec 14Dec 23Dec 31Jan 5Jan 13Jan 23Feb 5
16°FDec 11Dec 23Dec 31Jan 4Jan 12Jan 19Jan 26Feb 2Feb 14

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°F222215210205201196192188180
32°F251242235230224220215210201
28°F288273264256251244238232223
24°F322309299290283276268259249
20°F365348334327318310303293281
16°F365365365365357344334324308

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
99% of years
20°F or colder
91% of years
16°F or colder
61% 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
2,824
Cooling degree days, base 65°F
1,697
Growing degree days, base 40°F
8,124
Growing degree days, base 45°F
6,506
Growing degree days, base 50°F
5,043
Growing degree days, base 55°F
3,751
Growing degree days, base 60°F
2,633

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January632153
February526158
March4048149
April18541318
May44152574
June3322769
July0445910
August0400865
September8249691
October12566411
November3598160
December538485

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 km from Alliance. 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 USC00310576 (Bayboro 3 Sw). Public domain.