Indian River climate

Indian River Frost Dates and Growing Season

NOAA 1991-2020 normals for Pellston Rgnl AP, 22 km from Indian River, elevation 705 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pellston Rgnl AP. 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 31 and the first fall freeze around September 18, a growing season of about 108 days.

Median at 32°F
last May 31, first September 18
Median at 28°F
last May 19, first October 1

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°F–––––––––
32°FJun 21Jun 11Jun 6Jun 2May 31May 29May 26May 22May 16
28°FJun 2May 29May 26May 22May 19May 16May 12May 7Apr 30
24°FMay 22May 16May 12May 8May 4May 1Apr 28Apr 26Apr 21
20°FMay 9May 3Apr 30Apr 27Apr 24Apr 21Apr 19Apr 14Apr 9
16°FApr 28Apr 23Apr 19Apr 16Apr 13Apr 9Apr 6Apr 3Mar 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°F–––––––––
32°FSep 2Sep 9Sep 13Sep 16Sep 18Sep 21Sep 26Sep 29Oct 3
28°FSep 17Sep 22Sep 26Sep 29Oct 1Oct 4Oct 6Oct 10Oct 17
24°FSep 30Oct 4Oct 7Oct 12Oct 15Oct 19Oct 24Oct 29Nov 3
20°FOct 13Oct 19Oct 25Oct 29Nov 1Nov 4Nov 7Nov 12Nov 18
16°FOct 31Nov 3Nov 6Nov 10Nov 13Nov 17Nov 21Nov 26Dec 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°F1049689837771655847
32°F131123118113108102978979
28°F159152146140136131127121114
24°F187179173168163158154148141
20°F212206199195190185180174166
16°F237230224219214210206200192

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
8,391
Cooling degree days, base 65°F
254
Growing degree days, base 40°F
3,525
Growing degree days, base 45°F
2,594
Growing degree days, base 50°F
1,796
Growing degree days, base 55°F
1,127
Growing degree days, base 60°F
601

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,46300
February1,31600
March1,17804
April767120
May40913146
June14250362
July6092498
August7972457
September25324244
October595359
November89307
December1,23500

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 22 km from Indian River. 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 USW00014841 (Pellston Rgnl AP). Public domain.