Sunnyside climate

Sunnyside Frost Dates and Growing Season

NOAA 1991-2020 normals for Sunnyside, 0.1 km from Sunnyside, elevation 747 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sunnyside. 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 1 and the first fall freeze around October 6, a growing season of about 157 days.

Median at 36°F
last May 16, first September 25
Median at 32°F
last May 1, first October 6
Median at 28°F
last April 15, first October 19

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 7May 30May 25May 20May 16May 13May 9May 5May 1
32°FMay 18May 11May 7May 3May 1Apr 29Apr 26Apr 23Apr 16
28°FMay 1Apr 28Apr 23Apr 19Apr 15Apr 11Apr 7Apr 2Mar 28
24°FApr 14Apr 6Apr 1Mar 29Mar 25Mar 21Mar 16Mar 11Mar 5
20°FMar 26Mar 17Mar 12Mar 8Mar 5Mar 1Feb 26Feb 20Feb 11
16°FMar 9Mar 2Feb 27Feb 22Feb 16Feb 10Feb 3Jan 25Jan 11

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 10Sep 16Sep 19Sep 22Sep 25Sep 27Sep 30Oct 2Oct 7
32°FSep 25Sep 30Oct 2Oct 4Oct 6Oct 9Oct 12Oct 16Oct 22
28°FOct 5Oct 10Oct 14Oct 16Oct 19Oct 22Oct 26Oct 30Nov 4
24°FOct 17Oct 22Oct 26Oct 29Oct 31Nov 3Nov 7Nov 11Nov 17
20°FOct 27Nov 1Nov 5Nov 8Nov 12Nov 16Nov 20Nov 26Dec 4
16°FNov 4Nov 10Nov 15Nov 21Nov 26Dec 1Dec 6Dec 13Dec 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°F149142137132127123118113104
32°F177170165161157154150145137
28°F210202196191187182178172164
24°F246239232226221216211205196
20°F286272265258253248243236225
16°F324313302294285279271264254

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
99% 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
5,994
Cooling degree days, base 65°F
499
Growing degree days, base 40°F
4,611
Growing degree days, base 45°F
3,437
Growing degree days, base 50°F
2,448
Growing degree days, base 55°F
1,629
Growing degree days, base 60°F
978

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07600
February84400
March696011
April468170
May23525268
June9469425
July16211660
August26161600
September14932336
October484074
November81505
December1,09300

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 0.1 km from Sunnyside. 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 USC00458207 (Sunnyside). Public domain.