Valley Station climate

Valley Station Frost Dates and Growing Season

NOAA 1991-2020 normals for Louisville Intl AP, 13.8 km from Valley Station, elevation 488 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Louisville 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 31 and the first fall freeze around November 7, a growing season of about 222 days.

Median at 36°F
last April 11, first October 29
Median at 32°F
last March 31, first November 7
Median at 28°F
last March 20, first November 17

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

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°F219212207203199195191185178
32°F243236230226222219216211202
28°F270262254249244240235230223
24°F294285279272267262256250242
20°F320309302297292285279272261
16°F339330325319313307302295285

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
99% 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
3,936
Cooling degree days, base 65°F
1,742
Growing degree days, base 40°F
7,475
Growing degree days, base 45°F
6,048
Growing degree days, base 50°F
4,759
Growing degree days, base 55°F
3,611
Growing degree days, base 60°F
2,605

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January908017
February715127
March5248109
April22244299
May59160566
June3346793
July0462927
August0433897
September22233662
October19852335
November499498
December786128

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 13.8 km from Valley Station. 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 USW00093821 (Louisville Intl AP). Public domain.