Norway climate

Norway Frost Dates and Growing Season

NOAA 1991-2020 normals for Iron Mtn-Kingsford Wwtp, 14 km from Norway, elevation 1071 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Iron Mtn-Kingsford 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 17 and the first fall freeze around October 1, a growing season of about 135 days.

Median at 36°F
last May 29, first September 21
Median at 32°F
last May 17, first October 1
Median at 28°F
last May 4, first October 11

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 12Jun 6Jun 3May 31May 29May 26May 24May 20May 15
32°FMay 31May 26May 23May 20May 17May 14May 11May 7May 2
28°FMay 19May 14May 11May 7May 4May 2Apr 30Apr 27Apr 24
24°FMay 9May 2Apr 29Apr 27Apr 24Apr 22Apr 19Apr 15Apr 11
20°FApr 27Apr 22Apr 19Apr 16Apr 14Apr 11Apr 8Apr 5Apr 1
16°FApr 19Apr 14Apr 10Apr 7Apr 5Apr 2Mar 31Mar 29Mar 23

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 6Sep 12Sep 15Sep 18Sep 21Sep 23Sep 26Sep 30Oct 4
32°FSep 17Sep 22Sep 25Sep 28Oct 1Oct 3Oct 5Oct 9Oct 13
28°FSep 27Oct 2Oct 5Oct 8Oct 11Oct 14Oct 17Oct 20Oct 27
24°FOct 7Oct 13Oct 17Oct 21Oct 24Oct 28Oct 31Nov 3Nov 8
20°FOct 22Oct 28Nov 1Nov 2Nov 4Nov 8Nov 11Nov 15Nov 20
16°FNov 2Nov 6Nov 10Nov 13Nov 16Nov 18Nov 21Nov 25Nov 29

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°F13212612211911511110710397
32°F153147143139135132128124118
28°F176170164161157153148143136
24°F201195190184180176171166159
20°F224217212207204200196191184
16°F243236231227223219215210203

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
8,522
Cooling degree days, base 65°F
372
Growing degree days, base 40°F
3,811
Growing degree days, base 45°F
2,876
Growing degree days, base 50°F
2,062
Growing degree days, base 55°F
1,363
Growing degree days, base 60°F
791

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,57500
February1,33800
March1,14603
April737025
May35718187
June10373422
July36144574
August52105518
September22531277
October612154
November97503
December1,36700

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 km from Norway. 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 USC00204090 (Iron Mtn-Kingsford Wwtp). Public domain.