Geneva climate

Geneva Frost Dates and Growing Season

NOAA 1991-2020 normals for Bellingham 3 Ssw, 8.6 km from Geneva, elevation 15 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bellingham 3 Ssw. 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 1 and the first fall freeze around November 2, a growing season of about 216 days.

Median at 36°F
last April 27, first October 18
Median at 32°F
last April 1, first November 2
Median at 28°F
last March 6, first November 21

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 11May 6May 3Apr 30Apr 27Apr 23Apr 18Apr 13Apr 8
32°FApr 24Apr 14Apr 8Apr 3Apr 1Mar 28Mar 22Mar 18Mar 11
28°FMar 27Mar 20Mar 15Mar 10Mar 6Mar 1Feb 26Feb 21Feb 11
24°FMar 10Mar 1Feb 26Feb 21Feb 15Feb 8Jan 30Jan 17Jan 7
20°FFeb 25Feb 16Feb 6Jan 28Jan 19Jan 12Jan 5Dec 30Dec 10
16°FFeb 11Jan 30Jan 21Jan 13Jan 7Jan 1Dec 25Dec 13Dec 6

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

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°F200192187182177172167162153
32°F243233227221216210205198188
28°F291279271263257251246238229
24°F343329318311302295287277264
20°F365365357346338332324314303
16°F365365365365365361349340328

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
98% of years
20°F or colder
77% of years
16°F or colder
42% 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
4,845
Cooling degree days, base 65°F
78
Growing degree days, base 40°F
4,564
Growing degree days, base 45°F
3,076
Growing degree days, base 50°F
1,880
Growing degree days, base 55°F
994
Growing degree days, base 60°F
383

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January73807
February63305
March591016
April437056
May2811189
June1468312
July5434445
August5432443
September1743279
October403099
November587022
December74906

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 8.6 km from Geneva. 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 USC00450587 (Bellingham 3 Ssw). Public domain.