Bluewell climate

Bluewell Frost Dates and Growing Season

NOAA 1991-2020 normals for Bluefield Mercer CO AP, 5 km from Bluewell, elevation 2870 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bluefield Mercer CO AP. 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 21 and the first fall freeze around October 22, a growing season of about 182 days.

Median at 36°F
last May 4, first October 13
Median at 32°F
last April 21, first October 22
Median at 28°F
last April 9, first November 1

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 21May 15May 11May 7May 4May 1Apr 27Apr 23Apr 18
32°FMay 11May 5Apr 30Apr 25Apr 21Apr 18Apr 15Apr 11Apr 6
28°FApr 26Apr 21Apr 16Apr 13Apr 9Apr 7Apr 4Apr 1Mar 27
24°FApr 15Apr 9Apr 6Apr 3Mar 31Mar 29Mar 24Mar 19Mar 14
20°FApr 5Mar 31Mar 28Mar 24Mar 20Mar 17Mar 14Mar 8Mar 2
16°FMar 28Mar 23Mar 18Mar 15Mar 11Mar 7Mar 3Feb 26Feb 15

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 28Oct 3Oct 7Oct 10Oct 13Oct 15Oct 18Oct 21Oct 25
32°FOct 11Oct 14Oct 18Oct 20Oct 22Oct 25Oct 27Oct 30Nov 3
28°FOct 19Oct 23Oct 27Oct 29Nov 1Nov 3Nov 5Nov 9Nov 14
24°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 21Nov 28
20°FNov 5Nov 9Nov 14Nov 17Nov 21Nov 25Nov 30Dec 4Dec 11
16°FNov 13Nov 19Nov 26Nov 30Dec 3Dec 7Dec 11Dec 19Dec 27

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°F180173168165160156152147139
32°F203196191187182178173168160
28°F224217213209205201197191184
24°F249240235229225220216212206
20°F272264257251247241236230222
16°F298288281274268263258251241

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
5,219
Cooling degree days, base 65°F
536
Growing degree days, base 40°F
5,395
Growing degree days, base 45°F
4,109
Growing degree days, base 50°F
2,973
Growing degree days, base 55°F
1,992
Growing degree days, base 60°F
1,171

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02808
February841011
March708152
April38010168
May18236334
June41106515
July8174631
August13146598
September10156409
October3577180
November647151
December913016

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 5 km from Bluewell. 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 USW00003859 (Bluefield Mercer CO AP). Public domain.