Mellen climate

Mellen Frost Dates and Growing Season

NOAA 1991-2020 normals for Mellen 4 Ne, 5 km from Mellen, elevation 1300 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mellen 4 Ne. 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 May 26 and the first fall freeze around September 27, a growing season of about 125 days.

Median at 36°F
last June 5, first September 18
Median at 32°F
last May 26, first September 27
Median at 28°F
last May 12, first October 6

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°FJun 20Jun 14Jun 11Jun 8Jun 5Jun 2May 31May 29May 24
32°FJun 9Jun 3May 31May 29May 26May 23May 20May 15May 8
28°FMay 29May 24May 20May 16May 12May 9May 5Apr 30Apr 27
24°FMay 16May 10May 6May 2Apr 30Apr 28Apr 25Apr 22Apr 17
20°FMay 2Apr 29Apr 26Apr 23Apr 20Apr 17Apr 14Apr 11Apr 6
16°FApr 24Apr 20Apr 16Apr 13Apr 11Apr 7Apr 5Apr 2Mar 30

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 2Sep 7Sep 11Sep 14Sep 18Sep 21Sep 23Sep 26Sep 30
32°FSep 12Sep 18Sep 22Sep 24Sep 27Sep 30Oct 3Oct 6Oct 11
28°FSep 23Sep 28Oct 1Oct 4Oct 6Oct 9Oct 13Oct 17Oct 23
24°FOct 1Oct 6Oct 11Oct 15Oct 19Oct 22Oct 26Oct 30Nov 4
20°FOct 13Oct 19Oct 24Oct 28Nov 1Nov 2Nov 5Nov 9Nov 14
16°FOct 25Oct 31Nov 2Nov 6Nov 8Nov 12Nov 14Nov 18Nov 22

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°F12111511110710398948982
32°F149140134130125121117113106
28°F170163157153149144139134125
24°F192186181176170166161156149
20°F212206200196192187183178170
16°F231224219215211207203197190

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
9,186
Cooling degree days, base 65°F
265
Growing degree days, base 40°F
3,454
Growing degree days, base 45°F
2,561
Growing degree days, base 50°F
1,787
Growing degree days, base 55°F
1,135
Growing degree days, base 60°F
619

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,66100
February1,39400
March1,20204
April788125
May41815155
June16051350
July63101504
August8672452
September26524242
October657252
November1,04403
December1,44900

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 5 km from Mellen. 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 USC00475286 (Mellen 4 Ne). Public domain.