Gwinn climate

Gwinn Frost Dates and Growing Season

NOAA 1991-2020 normals for Ki Sawyer Wwtp, 7.7 km from Gwinn, elevation 1116 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ki Sawyer Wwtp. 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 13 and the first fall freeze around October 2, a growing season of about 141 days.

Median at 36°F
last May 28, first September 19
Median at 32°F
last May 13, first October 2
Median at 28°F
last May 1, first October 14

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 11Jun 6Jun 3May 31May 28May 25May 22May 18May 12
32°FMay 29May 24May 20May 17May 13May 10May 6May 2Apr 28
28°FMay 18May 12May 7May 3May 1Apr 29Apr 26Apr 24Apr 18
24°FMay 3Apr 29Apr 26Apr 23Apr 21Apr 18Apr 15Apr 12Apr 7
20°FApr 23Apr 19Apr 16Apr 14Apr 11Apr 8Apr 5Apr 2Mar 29
16°FApr 18Apr 14Apr 9Apr 6Apr 4Apr 2Mar 31Mar 27Mar 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 2Sep 6Sep 11Sep 16Sep 19Sep 22Sep 26Sep 29Oct 4
32°FSep 15Sep 20Sep 25Sep 29Oct 2Oct 5Oct 8Oct 11Oct 16
28°FSep 28Oct 4Oct 8Oct 11Oct 14Oct 17Oct 22Oct 26Nov 1
24°FOct 11Oct 19Oct 23Oct 27Oct 31Nov 3Nov 6Nov 11Nov 16
20°FOct 28Nov 1Nov 5Nov 9Nov 12Nov 15Nov 18Nov 22Nov 27
16°FNov 8Nov 13Nov 16Nov 19Nov 23Nov 26Nov 28Dec 1Dec 7

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°F13512712211811310910510092
32°F162155150145141136131126120
28°F186178173169165160156151144
24°F212204199195190185181175168
20°F235227223218214210205200194
16°F254246241237232228224218211

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
8,615
Cooling degree days, base 65°F
245
Growing degree days, base 40°F
3,438
Growing degree days, base 45°F
2,543
Growing degree days, base 50°F
1,770
Growing degree days, base 55°F
1,117
Growing degree days, base 60°F
600

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,48300
February1,32100
March1,18100
April79606
May4025148
June13039361
July49115532
August7172466
September26115222
October645033
November96803
December1,30800

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 7.7 km from Gwinn. 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 USC00204425 (Ki Sawyer Wwtp). Public domain.