Dayton climate

Dayton Frost Dates and Growing Season

NOAA 1991-2020 normals for Dayton Mcd, 0.5 km from Dayton, elevation 720 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dayton Mcd. 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 April 18 and the first fall freeze around October 25, a growing season of about 189 days.

Median at 36°F
last April 30, first October 16
Median at 32°F
last April 18, first October 25
Median at 28°F
last April 6, first November 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°FMay 15May 10May 5May 2Apr 30Apr 26Apr 23Apr 19Apr 14
32°FMay 5Apr 30Apr 25Apr 21Apr 18Apr 15Apr 11Apr 7Apr 3
28°FApr 24Apr 17Apr 13Apr 10Apr 6Apr 4Apr 1Mar 29Mar 23
24°FApr 11Apr 5Apr 2Mar 31Mar 28Mar 24Mar 21Mar 17Mar 12
20°FApr 1Mar 28Mar 24Mar 20Mar 17Mar 14Mar 11Mar 7Feb 28
16°FMar 22Mar 17Mar 13Mar 10Mar 6Mar 3Feb 28Feb 22Feb 14

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 4Oct 8Oct 11Oct 13Oct 16Oct 18Oct 20Oct 23Oct 26
32°FOct 13Oct 17Oct 21Oct 23Oct 25Oct 27Oct 30Nov 1Nov 7
28°FOct 23Oct 28Oct 31Nov 1Nov 4Nov 7Nov 10Nov 14Nov 18
24°FNov 1Nov 6Nov 10Nov 13Nov 16Nov 19Nov 22Nov 27Dec 2
20°FNov 10Nov 15Nov 20Nov 24Nov 27Dec 1Dec 4Dec 9Dec 18
16°FNov 20Nov 26Nov 30Dec 3Dec 7Dec 12Dec 17Dec 23Dec 30

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°F187181176173169165160155150
32°F209202198193189185181175168
28°F230224219215211207202198190
24°F258248244239234229225220214
20°F280273267261256251246241232
16°F302294288283278274267261252

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
5,432
Cooling degree days, base 65°F
1,191
Growing degree days, base 40°F
6,058
Growing degree days, base 45°F
4,827
Growing degree days, base 50°F
3,725
Growing degree days, base 55°F
2,749
Growing degree days, base 60°F
1,905

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14104
February94106
March757248
April38015174
May13399438
June16255690
July1349812
August3308770
September67142526
October33620205
November674043
December98408

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 0.5 km from Dayton. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00332067 (Dayton Mcd). Public domain.