Waverly climate

Waverly Frost Dates and Growing Season

NOAA 1991-2020 normals for Melvern Lake, 15 km from Waverly, elevation 1094 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Melvern Lake. 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 8 and the first fall freeze around October 30, a growing season of about 202 days.

Median at 36°F
last April 19, first October 21
Median at 32°F
last April 8, first October 30
Median at 28°F
last March 31, first November 7

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 3Apr 30Apr 26Apr 23Apr 19Apr 16Apr 14Apr 10Apr 5
32°FApr 22Apr 17Apr 14Apr 11Apr 8Apr 5Apr 2Mar 30Mar 24
28°FApr 13Apr 8Apr 5Apr 2Mar 31Mar 27Mar 22Mar 17Mar 11
24°FApr 4Mar 31Mar 26Mar 22Mar 19Mar 15Mar 11Mar 6Mar 1
20°FMar 28Mar 20Mar 16Mar 12Mar 8Mar 5Mar 2Feb 27Feb 20
16°FMar 17Mar 12Mar 8Mar 4Mar 1Feb 27Feb 22Feb 16Feb 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°FOct 6Oct 12Oct 16Oct 19Oct 21Oct 23Oct 25Oct 28Nov 1
32°FOct 16Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 8Nov 13
28°FOct 25Oct 31Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 24
24°FNov 1Nov 6Nov 11Nov 14Nov 18Nov 21Nov 26Dec 1Dec 4
20°FNov 10Nov 16Nov 20Nov 25Nov 29Dec 1Dec 5Dec 9Dec 16
16°FNov 20Nov 27Dec 1Dec 4Dec 8Dec 11Dec 16Dec 21Dec 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°F201195191187183179175170162
32°F224217211207202198194190183
28°F245238232227223218214208201
24°F266258252247242238233228219
20°F289278272267262258254248240
16°F309301294288283278272265258

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
4,785
Cooling degree days, base 65°F
1,520
Growing degree days, base 40°F
6,762
Growing degree days, base 45°F
5,441
Growing degree days, base 50°F
4,257
Growing degree days, base 55°F
3,208
Growing degree days, base 60°F
2,296

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,06602
February833013
March621477
April31821212
May102107472
June7303745
July0450914
August1409873
September45189595
October25737280
November594166
December94107

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 15 km from Waverly. 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 USC00145210 (Melvern Lake). Public domain.