Mayo climate

Mayo Frost Dates and Growing Season

NOAA 1991-2020 normals for Mayo, 6 km from Mayo, elevation 65 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mayo. 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 8 and the first fall freeze around November 25, a growing season of about 264 days.

Median at 36°F
last March 28, first November 12
Median at 32°F
last March 8, first November 25
Median at 28°F
last February 17, first December 13

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

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 5Nov 9Nov 12Nov 15Nov 19Nov 24Dec 3
32°FNov 5Nov 11Nov 16Nov 20Nov 25Nov 30Dec 3Dec 8Dec 20
28°FNov 19Nov 28Dec 3Dec 7Dec 13Dec 22Dec 31Jan 5Jan 18
24°FDec 3Dec 11Dec 19Dec 30Jan 3Jan 9Jan 15Jan 26Feb 5
20°FDec 12Dec 27Jan 1Jan 7Jan 12Jan 21Jan 28Feb 2Feb 10
16°F–––––––––

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°F261251243235230224218211202
32°F300288279270264259250241228
28°F339328318310304297288280265
24°F365365353342335330322312301
20°F365365365365365362350337329
16°F365365365365365365365365365

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
98% of years
24°F or colder
79% of years
20°F or colder
39% of years
16°F or colder
9% 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
1,195
Cooling degree days, base 65°F
2,749
Growing degree days, base 40°F
10,693
Growing degree days, base 45°F
8,906
Growing degree days, base 50°F
7,179
Growing degree days, base 55°F
5,555
Growing degree days, base 60°F
4,068

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January34721207
February22332256
March12580428
April50124524
May6307766
June0447897
July0515980
August0512977
September1398847
October34200632
November13676397
December27438270

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 6 km from Mayo. 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 USC00085539 (Mayo). Public domain.