Rolfe climate

Rolfe Frost Dates and Growing Season

NOAA 1991-2020 normals for Pocahontas, 14.4 km from Rolfe, elevation 1212 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pocahontas. 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 26 and the first fall freeze around October 7, a growing season of about 164 days.

Median at 36°F
last May 5, first September 28
Median at 32°F
last April 26, first October 7
Median at 28°F
last April 16, first October 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°FMay 18May 14May 11May 8May 5May 3May 1Apr 28Apr 23
32°FMay 8May 4May 2Apr 30Apr 26Apr 23Apr 20Apr 16Apr 11
28°FApr 30Apr 25Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3
24°FApr 21Apr 17Apr 12Apr 9Apr 7Apr 5Apr 2Mar 30Mar 22
20°FApr 14Apr 8Apr 5Apr 2Mar 31Mar 29Mar 23Mar 17Mar 12
16°FApr 6Apr 1Mar 29Mar 25Mar 21Mar 17Mar 13Mar 10Mar 5

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 16Sep 20Sep 23Sep 26Sep 28Sep 30Oct 3Oct 6Oct 10
32°FSep 25Sep 29Oct 1Oct 4Oct 7Oct 10Oct 12Oct 15Oct 20
28°FOct 3Oct 8Oct 11Oct 14Oct 17Oct 19Oct 22Oct 25Oct 30
24°FOct 12Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 4Nov 9
20°FOct 23Oct 28Oct 31Nov 2Nov 5Nov 7Nov 10Nov 13Nov 19
16°FNov 2Nov 4Nov 7Nov 10Nov 13Nov 16Nov 19Nov 23Nov 29

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°F163156152148145141137133128
32°F181176171167164160156151144
28°F200194190186182178175171165
24°F221214208204201198194189182
20°F240233228223219215210205199
16°F256249243238233229225220213

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
7,344
Cooling degree days, base 65°F
789
Growing degree days, base 40°F
4,951
Growing degree days, base 45°F
3,893
Growing degree days, base 50°F
2,942
Growing degree days, base 55°F
2,104
Growing degree days, base 60°F
1,384

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,50200
February1,23500
March968014
April540587
May21652322
June30190610
July6264724
August15190640
September13279405
October4779126
November905013
December1,32000

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 14.4 km from Rolfe. 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 USC00136719 (Pocahontas). Public domain.