Ava climate

Ava Frost Dates and Growing Season

NOAA 1991-2020 normals for Ava 6NW, 10.6 km from Ava, elevation 1253 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ava 6NW. 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 23 and the first fall freeze around October 17, a growing season of about 175 days.

Median at 36°F
last May 2, first October 7
Median at 32°F
last April 23, first October 17
Median at 28°F
last April 12, first October 24

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 11May 7May 4May 2Apr 30Apr 27Apr 24Apr 20
32°FMay 6May 1Apr 29Apr 26Apr 23Apr 20Apr 18Apr 15Apr 10
28°FApr 26Apr 21Apr 18Apr 15Apr 12Apr 9Apr 5Apr 3Mar 30
24°FApr 15Apr 9Apr 6Apr 3Apr 1Mar 29Mar 25Mar 20Mar 13
20°FApr 4Mar 30Mar 26Mar 23Mar 19Mar 15Mar 11Mar 6Feb 28
16°FMar 25Mar 19Mar 15Mar 11Mar 7Mar 3Feb 28Feb 24Feb 17

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 26Sep 30Oct 3Oct 5Oct 7Oct 9Oct 12Oct 15Oct 19
32°FOct 4Oct 8Oct 12Oct 14Oct 17Oct 19Oct 21Oct 24Oct 28
28°FOct 12Oct 17Oct 19Oct 22Oct 24Oct 26Oct 30Nov 1Nov 5
24°FOct 20Oct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 13Nov 19
20°FOct 31Nov 3Nov 6Nov 9Nov 13Nov 16Nov 20Nov 25Dec 1
16°FNov 7Nov 13Nov 17Nov 22Nov 25Nov 29Dec 3Dec 8Dec 17

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°F175169165161157154150146139
32°F193187182179175171167163157
28°F215209204200196192188183177
24°F242233226221217212209204198
20°F264256250244239234229223214
16°F291282274269263257251245237

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
4,825
Cooling degree days, base 65°F
1,157
Growing degree days, base 40°F
6,272
Growing degree days, base 45°F
4,965
Growing degree days, base 50°F
3,807
Growing degree days, base 55°F
2,789
Growing degree days, base 60°F
1,908

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02705
February829012
March619271
April33312190
May10983444
June7215658
July0361826
August2327790
September55131527
October29524232
November636145
December91308

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 10.6 km from Ava. 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 USC00230360 (Ava 6NW). Public domain.