Smiley climate

Smiley Frost Dates and Growing Season

NOAA 1991-2020 normals for Nixon, 12.9 km from Smiley, elevation 340 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Nixon. 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 7 and the first fall freeze around November 22, a growing season of about 260 days.

Median at 36°F
last March 21, first November 11
Median at 32°F
last March 7, first November 22
Median at 28°F
last February 20, first December 4

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 12Apr 5Apr 1Mar 27Mar 21Mar 17Mar 11Mar 7Feb 28
32°FMar 30Mar 22Mar 16Mar 11Mar 7Mar 3Feb 27Feb 22Feb 9
28°FMar 14Mar 7Mar 2Feb 26Feb 20Feb 13Feb 3Jan 27Jan 17
24°FMar 3Feb 24Feb 13Feb 6Jan 31Jan 24Jan 17Jan 5Dec 26
20°FFeb 16Feb 5Jan 27Jan 20Jan 13Jan 6Dec 31Dec 26Dec 14
16°FFeb 4Jan 26Jan 15Jan 10Jan 4Dec 31Dec 29Dec 23Dec 13

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 26Nov 1Nov 4Nov 8Nov 11Nov 15Nov 19Nov 24Nov 30
32°FNov 2Nov 8Nov 13Nov 17Nov 22Nov 26Dec 1Dec 4Dec 11
28°FNov 13Nov 20Nov 27Dec 1Dec 4Dec 9Dec 16Dec 28Jan 5
24°FNov 24Dec 2Dec 9Dec 17Dec 25Jan 1Jan 5Jan 14Jan 31
20°FDec 3Dec 11Dec 21Dec 28Jan 1Jan 5Jan 12Jan 23Feb 4
16°FDec 11Dec 17Dec 27Dec 30Jan 1Jan 6Jan 10Jan 19Feb 2

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°F261251244239233228222215205
32°F293280272266260253247240229
28°F331317308301293285277267255
24°F365356346338330321314302287
20°F365365365365365358347339325
16°F365365365365365365365365359

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
99% of years
24°F or colder
86% of years
20°F or colder
45% of years
16°F or colder
12% 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
1,549
Cooling degree days, base 65°F
2,971
Growing degree days, base 40°F
10,579
Growing degree days, base 45°F
8,825
Growing degree days, base 50°F
7,155
Growing degree days, base 55°F
5,606
Growing degree days, base 60°F
4,204

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January43010138
February29019196
March16463380
April46147552
May5341801
June0499949
July05781,043
August06041,069
September1420869
October41210636
November19463344
December37817179

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 12.9 km from Smiley. 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 USC00416368 (Nixon). Public domain.