Geneva climate

Geneva Frost Dates and Growing Season

NOAA 1991-2020 normals for Logan, 14.8 km from Geneva, elevation 722 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Logan. 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 14, a growing season of about 167 days.

Median at 36°F
last May 10, first October 5
Median at 32°F
last April 30, first October 14
Median at 28°F
last April 19, first October 24

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 26May 20May 16May 12May 10May 6May 3Apr 30Apr 26
32°FMay 17May 12May 8May 3Apr 30Apr 28Apr 25Apr 22Apr 18
28°FMay 8May 1Apr 26Apr 22Apr 19Apr 17Apr 13Apr 9Apr 4
24°FApr 20Apr 16Apr 12Apr 8Apr 5Apr 3Mar 31Mar 28Mar 22
20°FApr 11Apr 5Apr 2Mar 31Mar 28Mar 24Mar 21Mar 15Mar 9
16°FApr 1Mar 28Mar 23Mar 19Mar 16Mar 13Mar 9Mar 3Feb 25

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 23Sep 28Oct 1Oct 2Oct 5Oct 7Oct 10Oct 13Oct 17
32°FOct 2Oct 6Oct 9Oct 12Oct 14Oct 17Oct 19Oct 23Oct 26
28°FOct 9Oct 15Oct 19Oct 22Oct 24Oct 27Oct 30Nov 1Nov 5
24°FOct 21Oct 27Oct 31Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18
20°FNov 1Nov 5Nov 9Nov 12Nov 15Nov 18Nov 22Nov 28Dec 2
16°FNov 11Nov 16Nov 20Nov 24Nov 29Dec 1Dec 5Dec 9Dec 17

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°F166160155151147143139134129
32°F185179174171167162158153146
28°F207200195192187183179173165
24°F231224219214211207202197191
20°F256248242237233229224220213
16°F284274268262257252246241233

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
5,616
Cooling degree days, base 65°F
768
Growing degree days, base 40°F
5,416
Growing degree days, base 45°F
4,194
Growing degree days, base 50°F
3,121
Growing degree days, base 55°F
2,196
Growing degree days, base 60°F
1,409

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12004
February93705
March777133
April4236130
May18055351
June30148569
July3249711
August8207663
September8592459
October37611162
November693028
December98406

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 14.8 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 USC00334672 (Logan). Public domain.