Bellevue climate

Bellevue Frost Dates and Growing Season

NOAA 1991-2020 normals for Emsworth L/d Ohio Rvr, 3.3 km from Bellevue, elevation 717 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Emsworth L/d Ohio Rvr. 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 24 and the first fall freeze around October 27, a growing season of about 186 days.

Median at 36°F
last May 5, first October 16
Median at 32°F
last April 24, first October 27
Median at 28°F
last April 12, first November 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°FMay 21May 16May 12May 7May 5May 1Apr 28Apr 24Apr 20
32°FMay 11May 5Apr 30Apr 27Apr 24Apr 21Apr 18Apr 15Apr 9
28°FApr 26Apr 22Apr 18Apr 15Apr 12Apr 8Apr 5Apr 2Mar 28
24°FApr 17Apr 10Apr 6Apr 3Apr 1Mar 30Mar 26Mar 21Mar 15
20°FApr 4Mar 31Mar 27Mar 24Mar 19Mar 16Mar 13Mar 8Mar 3
16°FMar 26Mar 18Mar 15Mar 12Mar 8Mar 5Mar 1Feb 25Feb 17

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 6Oct 9Oct 12Oct 16Oct 18Oct 21Oct 24Oct 28
32°FOct 13Oct 18Oct 21Oct 24Oct 27Oct 29Nov 1Nov 3Nov 7
28°FOct 24Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 20
24°FNov 2Nov 7Nov 10Nov 13Nov 16Nov 20Nov 23Nov 28Dec 4
20°FNov 11Nov 17Nov 21Nov 25Nov 28Dec 1Dec 5Dec 11Dec 19
16°FNov 21Nov 27Dec 1Dec 5Dec 10Dec 17Dec 22Dec 26Jan 2

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°F185177172167163159154149142
32°F205199194190186181176172165
28°F229223218213209205201196189
24°F256247241236232227222216210
20°F280271265259254249244239231
16°F304295289283278272267259251

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
5,379
Cooling degree days, base 65°F
904
Growing degree days, base 40°F
5,667
Growing degree days, base 45°F
4,430
Growing degree days, base 50°F
3,337
Growing degree days, base 55°F
2,389
Growing degree days, base 60°F
1,574

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08804
February93204
March768130
April4106134
May16458369
June25176602
July2296759
August4248710
September63104491
October33215192
November647037
December94506

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 3.3 km from Bellevue. 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 USC00362574 (Emsworth L/d Ohio Rvr). Public domain.