Otis climate

Otis Frost Dates and Growing Season

NOAA 1991-2020 normals for Valparaiso Wtr Wks, 14.7 km from Otis, elevation 800 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Valparaiso Wtr Wks. 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 22 and the first fall freeze around October 25, a growing season of about 185 days.

Median at 36°F
last May 4, first October 13
Median at 32°F
last April 22, first October 25
Median at 28°F
last April 9, 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 22May 16May 10May 7May 4May 1Apr 28Apr 25Apr 20
32°FMay 6May 1Apr 28Apr 24Apr 22Apr 18Apr 15Apr 12Apr 7
28°FApr 24Apr 19Apr 16Apr 12Apr 9Apr 6Apr 3Mar 31Mar 25
24°FApr 12Apr 7Apr 3Apr 1Mar 30Mar 27Mar 23Mar 19Mar 12
20°FApr 2Mar 29Mar 26Mar 22Mar 19Mar 16Mar 12Mar 7Mar 1
16°FMar 26Mar 20Mar 16Mar 13Mar 9Mar 6Mar 2Feb 26Feb 18

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 30Oct 4Oct 7Oct 10Oct 13Oct 16Oct 19Oct 23Oct 26
32°FOct 12Oct 17Oct 20Oct 23Oct 25Oct 27Oct 30Nov 1Nov 6
28°FOct 24Oct 29Nov 1Nov 3Nov 5Nov 7Nov 11Nov 15Nov 21
24°FNov 3Nov 6Nov 10Nov 13Nov 17Nov 20Nov 23Nov 27Dec 2
20°FNov 9Nov 15Nov 19Nov 23Nov 26Nov 30Dec 2Dec 6Dec 13
16°FNov 18Nov 25Nov 29Dec 1Dec 4Dec 8Dec 13Dec 18Dec 23

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°F180174169165160156151146139
32°F205198193189185181176170163
28°F231223218214210206202197189
24°F257247242238234229225219212
20°F278268263259253248242237230
16°F295287282277272267261256247

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
6,038
Cooling degree days, base 65°F
778
Growing degree days, base 40°F
5,287
Growing degree days, base 45°F
4,121
Growing degree days, base 50°F
3,084
Growing degree days, base 55°F
2,172
Growing degree days, base 60°F
1,398

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24401
February1,01102
March826025
April4629115
May19750330
June40163573
July4252713
August10207662
September9487444
October35811182
November711034
December1,08003

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 14.7 km from Otis. 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 USC00128999 (Valparaiso Wtr Wks). Public domain.