Dunes City climate

Dunes City Frost Dates and Growing Season

NOAA 1991-2020 normals for Honeyman SP, 5.1 km from Dunes City, elevation 115 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Honeyman SP. 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 March 28 and the first fall freeze around November 22, a growing season of about 237 days.

Median at 36°F
last April 30, first October 31
Median at 32°F
last March 28, first November 22
Median at 28°F
last February 18, first December 15

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 20May 13May 8May 3Apr 30Apr 27Apr 22Apr 15Apr 7
32°FApr 21Apr 11Apr 5Apr 1Mar 28Mar 22Mar 14Mar 3Feb 23
28°FMar 18Mar 8Feb 28Feb 24Feb 18Feb 9Jan 26Jan 7Dec 21
24°FFeb 27Feb 15Jan 31Jan 14Jan 3Dec 29Dec 20Dec 13Dec 6
20°F–––––––––
16°F–––––––––

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°FOct 8Oct 17Oct 23Oct 27Oct 31Nov 3Nov 8Nov 15Nov 23
32°FOct 28Nov 4Nov 11Nov 16Nov 22Nov 28Dec 2Dec 9Dec 20
28°FNov 13Nov 25Dec 2Dec 8Dec 15Dec 25Jan 2Jan 16Feb 12
24°FDec 1Dec 8Dec 12Dec 18Dec 26Jan 1Jan 10Jan 31Feb 21
20°F–––––––––
16°F–––––––––

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°F216205196190183177172164154
32°F279263253245237232224214202
28°F362342329317308299290278262
24°F365365365365365365355341321
20°F365365365365365365365365365
16°F365365365365365365365365365

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
90% of years
24°F or colder
38% of years
20°F or colder
7% of years
16°F or colder
1% 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
5,141
Cooling degree days, base 65°F
15
Growing degree days, base 40°F
4,078
Growing degree days, base 45°F
2,511
Growing degree days, base 50°F
1,296
Growing degree days, base 55°F
492
Growing degree days, base 60°F
106

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January66005
February571010
March587015
April475141
May3841101
June2651188
July1923276
August1863282
September2174238
October3791110
November540025
December68406

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 5.1 km from Dunes City. 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 USC00353995 (Honeyman SP). Public domain.