Oak Harbor climate

Oak Harbor Frost Dates and Growing Season

NOAA 1991-2020 normals for Fremont, 19.4 km from Oak Harbor, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fremont. 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 26 and the first fall freeze around October 23, a growing season of about 179 days.

Median at 36°F
last May 6, first October 9
Median at 32°F
last April 26, first October 23
Median at 28°F
last April 14, first November 2

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 21May 17May 12May 9May 6May 2Apr 30Apr 26Apr 22
32°FMay 13May 7May 2Apr 30Apr 26Apr 23Apr 20Apr 15Apr 11
28°FApr 30Apr 25Apr 21Apr 17Apr 14Apr 10Apr 7Apr 3Mar 31
24°FApr 17Apr 11Apr 6Apr 3Apr 1Mar 30Mar 27Mar 22Mar 16
20°FApr 5Mar 31Mar 29Mar 25Mar 22Mar 18Mar 15Mar 11Mar 4
16°FMar 29Mar 23Mar 19Mar 15Mar 13Mar 9Mar 5Mar 1Feb 21

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 27Oct 1Oct 4Oct 6Oct 9Oct 12Oct 15Oct 18Oct 23
32°FOct 8Oct 13Oct 17Oct 20Oct 23Oct 26Oct 28Nov 1Nov 4
28°FOct 21Oct 26Oct 29Nov 1Nov 2Nov 5Nov 8Nov 13Nov 19
24°FNov 1Nov 5Nov 8Nov 12Nov 15Nov 19Nov 23Nov 26Dec 1
20°FNov 9Nov 14Nov 19Nov 23Nov 27Nov 30Dec 3Dec 8Dec 16
16°FNov 20Nov 26Nov 30Dec 3Dec 7Dec 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°F177170165161157153149145137
32°F199192187183179175172167159
28°F222216211207203199194188182
24°F250243237232228223219215208
20°F273265259253248243238234226
16°F294285280275270266260254245

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
6,028
Cooling degree days, base 65°F
874
Growing degree days, base 40°F
5,361
Growing degree days, base 45°F
4,196
Growing degree days, base 50°F
3,170
Growing degree days, base 55°F
2,276
Growing degree days, base 60°F
1,505

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20601
February1,02803
March861125
April4875101
May20059339
June31192612
July3284745
August7223680
September9096459
October37814170
November704032
December1,03405

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 19.4 km from Oak Harbor. 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 USC00332974 (Fremont). Public domain.