Ellis climate

Ellis Frost Dates and Growing Season

NOAA 1991-2020 normals for Cedar Bluff Dam, 21 km from Ellis, elevation 2135 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cedar Bluff Dam. 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 25 and the first fall freeze around October 17, a growing season of about 174 days.

Median at 36°F
last May 3, first October 8
Median at 32°F
last April 25, first October 17
Median at 28°F
last April 15, first October 26

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 16May 11May 8May 6May 3May 2Apr 30Apr 26Apr 21
32°FMay 7May 3May 1Apr 29Apr 25Apr 23Apr 20Apr 16Apr 12
28°FApr 29Apr 25Apr 21Apr 18Apr 15Apr 12Apr 9Apr 5Mar 31
24°FApr 21Apr 16Apr 12Apr 8Apr 5Apr 2Mar 30Mar 24Mar 16
20°FApr 14Apr 7Apr 2Mar 30Mar 25Mar 20Mar 15Mar 11Mar 4
16°FApr 1Mar 27Mar 20Mar 16Mar 12Mar 8Mar 4Mar 1Feb 24

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 25Sep 30Oct 3Oct 5Oct 8Oct 10Oct 13Oct 16Oct 20
32°FOct 3Oct 9Oct 13Oct 15Oct 17Oct 20Oct 22Oct 25Oct 28
28°FOct 14Oct 18Oct 21Oct 23Oct 26Oct 28Oct 31Nov 3Nov 7
24°FOct 20Oct 25Oct 29Nov 1Nov 3Nov 6Nov 9Nov 13Nov 19
20°FOct 29Nov 1Nov 5Nov 9Nov 12Nov 16Nov 20Nov 24Nov 29
16°FNov 4Nov 10Nov 14Nov 18Nov 23Nov 26Nov 29Dec 3Dec 8

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°F174168164161157154150145139
32°F193187182177174170166162154
28°F212206202198194191187182176
24°F236229223218213209204200192
20°F258249242238233227223217208
16°F279271265258253248242235225

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
5,344
Cooling degree days, base 65°F
1,373
Growing degree days, base 40°F
6,245
Growing degree days, base 45°F
4,994
Growing degree days, base 50°F
3,889
Growing degree days, base 55°F
2,921
Growing degree days, base 60°F
2,082

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08801
February89307
March684150
April39910154
May14881408
June13277714
July1438902
August4366828
September61175567
October32924223
November696035
December1,02702

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 21 km from Ellis. 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 USC00141383 (Cedar Bluff Dam). Public domain.