Rib Lake climate

Rib Lake Frost Dates and Growing Season

NOAA 1991-2020 normals for Medford, 23.4 km from Rib Lake, elevation 1470 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Medford. 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 11 and the first fall freeze around October 1, a growing season of about 141 days.

Median at 36°F
last May 23, first September 22
Median at 32°F
last May 11, first October 1
Median at 28°F
last May 1, 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 6Jun 1May 29May 26May 23May 20May 17May 13May 8
32°FMay 26May 21May 18May 14May 11May 8May 5May 3Apr 29
28°FMay 15May 10May 6May 3May 1Apr 29Apr 26Apr 23Apr 18
24°FMay 3Apr 29Apr 26Apr 23Apr 20Apr 17Apr 14Apr 10Apr 5
20°FApr 25Apr 20Apr 16Apr 13Apr 9Apr 7Apr 4Apr 1Mar 28
16°FApr 17Apr 11Apr 7Apr 5Apr 2Mar 31Mar 29Mar 25Mar 19

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 7Sep 13Sep 16Sep 19Sep 22Sep 25Sep 28Oct 1Oct 4
32°FSep 17Sep 22Sep 26Sep 28Oct 1Oct 4Oct 6Oct 9Oct 13
28°FSep 27Oct 1Oct 5Oct 8Oct 11Oct 14Oct 17Oct 20Oct 25
24°FOct 8Oct 13Oct 16Oct 20Oct 23Oct 26Oct 30Nov 1Nov 6
20°FOct 19Oct 25Oct 29Nov 1Nov 3Nov 5Nov 9Nov 12Nov 16
16°FNov 1Nov 3Nov 6Nov 9Nov 13Nov 15Nov 17Nov 21Nov 25

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°F140133129125122117113109102
32°F159152149145141138134130124
28°F180173168164160157153148141
24°F203196192188184180175171164
20°F225219213209206201197192187
16°F243237232227223219215211205

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
8,763
Cooling degree days, base 65°F
334
Growing degree days, base 40°F
3,804
Growing degree days, base 45°F
2,865
Growing degree days, base 50°F
2,038
Growing degree days, base 55°F
1,331
Growing degree days, base 60°F
754

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,66000
February1,38000
March1,14706
April707033
May34016194
June9769423
July35128558
August5490501
September23330271
October632250
November1,02503
December1,45400

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 23.4 km from Rib Lake. 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 USC00475255 (Medford). Public domain.