Spencerville climate

Spencerville Frost Dates and Growing Season

NOAA 1991-2020 normals for Aztec Ruins Nm, 5.4 km from Spencerville, elevation 5644 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Aztec Ruins Nm. 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 12 and the first fall freeze around October 6, a growing season of about 147 days.

Median at 36°F
last May 27, first September 30
Median at 32°F
last May 12, first October 6
Median at 28°F
last April 30, first October 15

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 11Jun 6Jun 2May 30May 27May 24May 20May 17May 11
32°FMay 30May 24May 19May 15May 12May 8May 5May 2Apr 29
28°FMay 12May 7May 4May 2Apr 30Apr 28Apr 25Apr 21Apr 16
24°FMay 2Apr 29Apr 25Apr 22Apr 19Apr 16Apr 12Apr 8Apr 3
20°FApr 23Apr 16Apr 11Apr 8Apr 5Apr 1Mar 28Mar 21Mar 12
16°FApr 10Apr 1Mar 26Mar 18Mar 13Mar 8Mar 3Feb 27Feb 20

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

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°F141136132128124120116112106
32°F164158155150147143139134127
28°F186179174171167164159154149
24°F210203197194190184180175169
20°F239230224219214208203197191
16°F272263257251245238231224212

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
5,163
Cooling degree days, base 65°F
914
Growing degree days, base 40°F
5,633
Growing degree days, base 45°F
4,370
Growing degree days, base 50°F
3,277
Growing degree days, base 55°F
2,342
Growing degree days, base 60°F
1,555

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03700
February78401
March623021
April4010108
May16624329
June21171600
July0343807
August1281746
September5393491
October3532161
November705012
December1,02000

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 5.4 km from Spencerville. 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 USC00290692 (Aztec Ruins Nm). Public domain.