Stephen climate

Stephen Frost Dates and Growing Season

NOAA 1991-2020 normals for Argyle, 13.7 km from Stephen, elevation 847 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Argyle. 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 May 15 and the first fall freeze around September 26, a growing season of about 134 days.

Median at 36°F
last May 24, first September 16
Median at 32°F
last May 15, first September 26
Median at 28°F
last May 4, first October 6

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°FJun 5Jun 1May 30May 27May 24May 22May 19May 15May 11
32°FMay 28May 24May 21May 17May 15May 12May 9May 5May 1
28°FMay 21May 15May 11May 7May 4May 1Apr 29Apr 25Apr 20
24°FMay 10May 5May 1Apr 29Apr 25Apr 22Apr 18Apr 14Apr 7
20°FApr 30Apr 25Apr 21Apr 18Apr 14Apr 10Apr 7Apr 4Apr 1
16°FApr 21Apr 16Apr 12Apr 8Apr 6Apr 4Apr 2Mar 30Mar 23

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 1Sep 7Sep 11Sep 14Sep 16Sep 19Sep 21Sep 23Sep 27
32°FSep 13Sep 18Sep 21Sep 24Sep 26Sep 29Oct 1Oct 3Oct 8
28°FSep 24Sep 28Oct 1Oct 3Oct 6Oct 9Oct 12Oct 16Oct 20
24°FOct 1Oct 6Oct 10Oct 13Oct 16Oct 19Oct 23Oct 27Oct 31
20°FOct 10Oct 15Oct 19Oct 24Oct 28Oct 30Nov 1Nov 5Nov 9
16°FOct 19Oct 26Oct 30Nov 1Nov 3Nov 6Nov 9Nov 12Nov 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°F13212612111711411010610194
32°F153146142138134131126121114
28°F174167161157153150145141134
24°F194187182178173169165159152
20°F215208203198194189184179171
16°F229223218214210206202197189

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
9,613
Cooling degree days, base 65°F
375
Growing degree days, base 40°F
3,766
Growing degree days, base 45°F
2,860
Growing degree days, base 50°F
2,057
Growing degree days, base 55°F
1,364
Growing degree days, base 60°F
796

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,84600
February1,55300
March1,27402
April737027
May36016187
June9577434
July32139572
August52111524
September24130264
October669248
November1,14301
December1,61200

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 13.7 km from Stephen. 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 USC00210252 (Argyle). Public domain.