Lyon County climate

Lyon County Frost Dates and Growing Season

NOAA 1991-2020 normals for Eddyville 5S, 3.4 km from Lyon County, elevation 523 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Eddyville 5S. 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 27 and the first fall freeze around November 8, a growing season of about 225 days.

Median at 36°F
last April 7, first October 29
Median at 32°F
last March 27, first November 8
Median at 28°F
last March 15, first November 19

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 23Apr 17Apr 13Apr 10Apr 7Apr 4Apr 1Mar 29Mar 23
32°FApr 12Apr 6Apr 2Mar 31Mar 27Mar 24Mar 20Mar 16Mar 10
28°FApr 1Mar 28Mar 23Mar 18Mar 15Mar 11Mar 7Mar 3Feb 26
24°FMar 20Mar 15Mar 10Mar 6Mar 2Feb 28Feb 23Feb 18Feb 11
20°FMar 12Mar 4Feb 28Feb 24Feb 20Feb 15Feb 10Feb 4Jan 28
16°FMar 3Feb 24Feb 18Feb 12Feb 7Feb 2Jan 30Jan 24Jan 12

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 15Oct 20Oct 24Oct 26Oct 29Oct 31Nov 2Nov 5Nov 11
32°FOct 27Oct 31Nov 3Nov 5Nov 8Nov 11Nov 15Nov 19Nov 26
28°FNov 5Nov 9Nov 13Nov 16Nov 19Nov 23Nov 27Dec 1Dec 8
24°FNov 11Nov 17Nov 22Nov 26Nov 30Dec 4Dec 9Dec 15Dec 22
20°FNov 22Nov 28Dec 2Dec 7Dec 12Dec 19Dec 24Dec 29Jan 7
16°FDec 1Dec 9Dec 17Dec 23Dec 28Jan 1Jan 7Jan 14Jan 23

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°F225216211207202198195189183
32°F249242236230225221217212205
28°F274266259255250245240234225
24°F300290284278272267262256248
20°F325315307301295290282275267
16°F348335330325318312305296288

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
96% 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
3,354
Cooling degree days, base 65°F
1,902
Growing degree days, base 40°F
8,039
Growing degree days, base 45°F
6,516
Growing degree days, base 50°F
5,132
Growing degree days, base 55°F
3,901
Growing degree days, base 60°F
2,823

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January814022
February624148
March42710151
April16951346
May43176598
June1364813
July0477942
August0468933
September14271708
October14476403
November4187132
December701035

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 3.4 km from Lyon County. 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 USC00152442 (Eddyville 5S). Public domain.