White Haven climate

White Haven Frost Dates and Growing Season

NOAA 1991-2020 normals for Libby 1 Ne RS, 6.7 km from White Haven, elevation 2096 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Libby 1 Ne RS. 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 23 and the first fall freeze around September 21, a growing season of about 120 days.

Median at 32°F
last May 23, first September 21
Median at 28°F
last May 7, first October 5

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°F–––––––––
32°FJun 7Jun 2May 29May 26May 23May 20May 17May 14May 9
28°FMay 20May 16May 13May 10May 7May 4Apr 30Apr 28Apr 23
24°FMay 5May 1Apr 27Apr 23Apr 19Apr 14Apr 8Apr 3Mar 29
20°FApr 16Apr 5Mar 31Mar 28Mar 24Mar 18Mar 13Mar 7Mar 2
16°FMar 25Mar 18Mar 14Mar 9Mar 5Mar 2Feb 28Feb 22Feb 14

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°F–––––––––
32°FSep 3Sep 8Sep 13Sep 18Sep 21Sep 25Sep 29Oct 3Oct 8
28°FSep 20Sep 26Sep 30Oct 2Oct 5Oct 10Oct 14Oct 20Oct 29
24°FOct 1Oct 6Oct 13Oct 18Oct 23Oct 28Nov 1Nov 7Nov 18
20°FOct 12Oct 20Oct 27Nov 2Nov 7Nov 12Nov 19Nov 24Dec 1
16°FOct 25Nov 4Nov 10Nov 17Nov 23Nov 28Dec 1Dec 7Dec 15

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°F11010195908580746758
32°F14313613012412011611010496
28°F177169162157152148143139130
24°F217207198191186180173166158
20°F260246238232226219210203191
16°F291279272265258251243236223

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
6,774
Cooling degree days, base 65°F
379
Growing degree days, base 40°F
4,038
Growing degree days, base 45°F
2,986
Growing degree days, base 50°F
2,107
Growing degree days, base 55°F
1,375
Growing degree days, base 60°F
791

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14900
February93700
March79702
April552034
May2999198
June11944376
July28159597
August35142572
September19725287
October584041
November90901
December1,16900

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 6.7 km from White Haven. 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 USC00245015 (Libby 1 Ne RS). Public domain.