Bloomfield climate

Bloomfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Crofton, 19.5 km from Bloomfield, elevation 1400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Crofton. 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 30 and the first fall freeze around October 8, a growing season of about 160 days.

Median at 36°F
last May 9, first September 30
Median at 32°F
last April 30, first October 8
Median at 28°F
last April 20, first October 18

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 22May 18May 14May 12May 9May 6May 4May 1Apr 28
32°FMay 13May 9May 6May 3Apr 30Apr 28Apr 25Apr 21Apr 16
28°FMay 5Apr 30Apr 27Apr 23Apr 20Apr 17Apr 14Apr 10Apr 6
24°FApr 25Apr 20Apr 17Apr 13Apr 10Apr 7Apr 5Apr 2Mar 29
20°FApr 17Apr 12Apr 8Apr 5Apr 3Mar 31Mar 28Mar 23Mar 17
16°FApr 10Apr 4Apr 1Mar 29Mar 25Mar 21Mar 18Mar 14Mar 8

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 17Sep 22Sep 25Sep 27Sep 30Oct 1Oct 4Oct 7Oct 11
32°FSep 26Sep 30Oct 3Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21
28°FOct 3Oct 8Oct 12Oct 15Oct 18Oct 20Oct 22Oct 26Oct 30
24°FOct 12Oct 17Oct 21Oct 24Oct 26Oct 29Nov 1Nov 3Nov 8
20°FOct 21Oct 26Oct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 18
16°FOct 31Nov 3Nov 6Nov 9Nov 12Nov 14Nov 17Nov 21Nov 26

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°F159153149146143140136132126
32°F178172168163160156152148143
28°F198191186183178174170166159
24°F218211205201198194189184177
20°F236229224219215211207202195
16°F252246241237232227223217210

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
6,987
Cooling degree days, base 65°F
863
Growing degree days, base 40°F
5,090
Growing degree days, base 45°F
3,999
Growing degree days, base 50°F
3,031
Growing degree days, base 55°F
2,181
Growing degree days, base 60°F
1,457

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,38900
February1,13702
March907122
April532689
May22846305
June34178594
July5296756
August13231683
September11996434
October4759128
November878018
December1,27100

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 19.5 km from Bloomfield. 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 USC00252037 (Crofton). Public domain.