Bishop climate

Bishop Frost Dates and Growing Season

NOAA 1991-2020 normals for Bishop, 0.5 km from Bishop, elevation 67 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bishop. 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 13 and the first fall freeze around December 7, a growing season of about 305 days.

Median at 36°F
last February 28, first November 25
Median at 32°F
last February 13, first December 7
Median at 28°F
last January 26, first December 29

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°FMar 18Mar 12Mar 7Mar 3Feb 28Feb 25Feb 19Feb 12Jan 31
32°FMar 12Mar 3Feb 26Feb 20Feb 13Feb 5Jan 28Jan 18Jan 4
28°FMar 3Feb 21Feb 12Feb 4Jan 26Jan 15Jan 6Dec 29Dec 16
24°FFeb 25Feb 9Feb 1Jan 15Jan 8Jan 4Dec 30Dec 21Dec 14
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 9Nov 14Nov 18Nov 22Nov 25Nov 29Dec 3Dec 9Dec 18
32°FNov 17Nov 24Nov 29Dec 3Dec 7Dec 15Dec 21Dec 29Jan 8
28°FNov 30Dec 6Dec 13Dec 20Dec 29Jan 2Jan 8Jan 19Feb 7
24°FDec 9Dec 17Dec 25Jan 1Jan 4Jan 7Jan 15Feb 3Feb 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°F308294285278272266261255246
32°F342330319312305296287277265
28°F365365361350340333324311298
24°F365365365365365365364350336
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
98% of years
28°F or colder
75% of years
24°F or colder
31% of years
20°F or colder
7% 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
954
Cooling degree days, base 65°F
3,672
Growing degree days, base 40°F
11,853
Growing degree days, base 45°F
10,054
Growing degree days, base 50°F
8,299
Growing degree days, base 55°F
6,629
Growing degree days, base 60°F
5,083

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January29329243
February18855311
March83126513
April18252685
May1426890
June05521,002
July06251,090
August06571,122
September0488938
October11312766
November106106457
December25446284

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 0.5 km from Bishop. 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 USC00410805 (Bishop). Public domain.