Bend climate

Bend Frost Dates and Growing Season

NOAA 1991-2020 normals for Red Bluff Muni AP, 12.1 km from Bend, elevation 353 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Red Bluff Muni AP. 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 February 22 and the first fall freeze around November 29, a growing season of about 281 days.

Median at 36°F
last March 30, first November 15
Median at 32°F
last February 22, first November 29
Median at 28°F
last January 13, 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°FApr 19Apr 12Apr 8Apr 4Mar 30Mar 24Mar 17Mar 11Mar 1
32°FMar 30Mar 14Mar 5Feb 28Feb 22Feb 16Feb 8Jan 31Jan 17
28°FFeb 21Feb 5Jan 28Jan 20Jan 13Jan 5Dec 31Dec 25Dec 18
24°FJan 25Jan 15Jan 8Jan 3Dec 31Dec 28Dec 24Dec 18Dec 11
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°FNov 1Nov 6Nov 9Nov 12Nov 15Nov 18Nov 21Nov 25Nov 30
32°FNov 12Nov 18Nov 22Nov 26Nov 29Dec 1Dec 6Dec 10Dec 18
28°FNov 28Dec 2Dec 6Dec 11Dec 15Dec 19Dec 26Jan 1Jan 12
24°FDec 5Dec 12Dec 17Dec 21Dec 25Dec 29Jan 2Jan 8Jan 19
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°F261251243236231225220213205
32°F321305297288281274265254242
28°F365357348342336331323313301
24°F365365365365365365360352342
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
86% of years
24°F or colder
35% of years
20°F or colder
5% of years
16°F or colder
0% 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
2,525
Cooling degree days, base 65°F
1,926
Growing degree days, base 40°F
8,541
Growing degree days, base 45°F
6,795
Growing degree days, base 50°F
5,227
Growing degree days, base 55°F
3,910
Growing degree days, base 60°F
2,822

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January547031
February398075
March3223167
April18725293
May57152560
June6348792
July0527992
August0462927
September5315760
October8691470
November3502135
December566026

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 12.1 km from Bend. 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 USW00024216 (Red Bluff Muni AP). Public domain.