Midway climate

Midway Frost Dates and Growing Season

NOAA 1991-2020 normals for Roswell Ind Air Pk, 5.6 km from Midway, elevation 3649 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Roswell Ind Air Pk. 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 29 and the first fall freeze around November 7, a growing season of about 223 days.

Median at 36°F
last April 9, first October 30
Median at 32°F
last March 29, first November 7
Median at 28°F
last March 10, first November 16

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 24Apr 19Apr 16Apr 12Apr 9Apr 6Apr 3Mar 31Mar 25
32°FApr 15Apr 9Apr 4Apr 1Mar 29Mar 24Mar 19Mar 13Mar 8
28°FApr 1Mar 25Mar 19Mar 14Mar 10Mar 6Mar 3Feb 27Feb 21
24°FMar 14Mar 8Mar 4Mar 1Feb 26Feb 22Feb 17Feb 11Feb 4
20°FMar 4Feb 25Feb 18Feb 13Feb 7Feb 2Jan 28Jan 21Jan 11
16°FFeb 16Feb 5Jan 30Jan 23Jan 17Jan 11Jan 5Dec 30Dec 19

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 19Oct 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 6Nov 10
32°FOct 26Oct 30Nov 2Nov 5Nov 7Nov 9Nov 12Nov 15Nov 19
28°FNov 2Nov 7Nov 11Nov 14Nov 16Nov 19Nov 22Nov 26Dec 1
24°FNov 8Nov 14Nov 18Nov 22Nov 26Nov 29Dec 2Dec 6Dec 10
20°FNov 17Nov 24Nov 29Dec 4Dec 8Dec 11Dec 15Dec 20Dec 27
16°FNov 27Dec 4Dec 10Dec 15Dec 20Dec 24Dec 29Jan 5Jan 18

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°F222215210206202198194190184
32°F247239233228223219215209200
28°F272264258254250244239233223
24°F299291284278273269264257249
20°F337325318311305298292283272
16°F365359352346340333327317305

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
89% 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
2,876
Cooling degree days, base 65°F
2,236
Growing degree days, base 40°F
8,656
Growing degree days, base 45°F
7,053
Growing degree days, base 50°F
5,604
Growing degree days, base 55°F
4,321
Growing degree days, base 60°F
3,201

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January691020
February481161
March3139204
April11763403
May20245690
June0479928
July05641,029
August0515980
September9291732
October12267420
November4222116
December701021

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 5.6 km from Midway. 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 USW00023009 (Roswell Ind Air Pk). Public domain.