Triana climate

Triana Frost Dates and Growing Season

NOAA 1991-2020 normals for Huntsville Intl AP, 8.1 km from Triana, elevation 624 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Huntsville Intl AP. 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 24 and the first fall freeze around November 8, a growing season of about 229 days.

Median at 36°F
last April 4, first October 30
Median at 32°F
last March 24, first November 8
Median at 28°F
last March 10, first November 20

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

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 17Oct 22Oct 25Oct 28Oct 30Nov 1Nov 3Nov 7Nov 12
32°FOct 27Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 19Nov 25
28°FNov 3Nov 8Nov 12Nov 16Nov 20Nov 24Nov 29Dec 3Dec 8
24°FNov 12Nov 19Nov 25Nov 29Dec 3Dec 8Dec 15Dec 26Jan 3
20°FNov 27Dec 5Dec 13Dec 21Dec 28Jan 1Jan 6Jan 12Jan 21
16°FDec 14Dec 24Jan 1Jan 4Jan 8Jan 12Jan 17Jan 23Feb 1

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°F229221216211207204200196189
32°F255246240234229225220215208
28°F284274267262256250244238230
24°F318306297290283277270262251
20°F349337329322315308302294281
16°F365365360351344336331323310

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
97% of years
16°F or colder
77% 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
2,831
Cooling degree days, base 65°F
2,107
Growing degree days, base 40°F
8,596
Growing degree days, base 45°F
7,002
Growing degree days, base 50°F
5,547
Growing degree days, base 55°F
4,243
Growing degree days, base 60°F
3,094

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January692147
February513270
March34916197
April13269395
May23220662
June0407856
July0505970
August0481945
September8306748
October12288438
November38310153
December609366

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 8.1 km from Triana. 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 USW00003856 (Huntsville Intl AP). Public domain.