Bayfield climate

Bayfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Ignacio 6ESE, 16.6 km from Bayfield, elevation 6548 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ignacio 6ESE. 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 23 and the first fall freeze around September 29, a growing season of about 128 days.

Median at 36°F
last June 5, first September 21
Median at 32°F
last May 23, first September 29
Median at 28°F
last May 7, first October 8

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 18Jun 13Jun 10Jun 7Jun 5Jun 2May 31May 29May 23
32°FJun 7Jun 2May 30May 27May 23May 20May 18May 15May 9
28°FMay 23May 17May 14May 10May 7May 5May 3Apr 30Apr 27
24°FMay 9May 4May 2Apr 30Apr 27Apr 24Apr 21Apr 19Apr 14
20°FApr 29Apr 23Apr 20Apr 16Apr 14Apr 11Apr 9Apr 6Apr 1
16°FApr 16Apr 10Apr 7Apr 3Mar 31Mar 28Mar 21Mar 15Mar 9

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 8Sep 13Sep 16Sep 18Sep 21Sep 23Sep 25Sep 27Sep 30
32°FSep 18Sep 23Sep 25Sep 27Sep 29Oct 1Oct 4Oct 6Oct 11
28°FSep 28Oct 2Oct 4Oct 6Oct 8Oct 11Oct 14Oct 17Oct 21
24°FOct 6Oct 10Oct 13Oct 16Oct 18Oct 21Oct 23Oct 27Nov 1
20°FOct 14Oct 19Oct 22Oct 25Oct 29Nov 1Nov 3Nov 7Nov 12
16°FOct 23Oct 28Nov 1Nov 5Nov 8Nov 12Nov 15Nov 19Nov 23

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°F123117112109106103999588
32°F147141135131128124120116109
28°F170164160156153149145141135
24°F191185181177173169165161154
20°F216209204200195191186182175
16°F248238231226221216211205197

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
6,967
Cooling degree days, base 65°F
256
Growing degree days, base 40°F
3,935
Growing degree days, base 45°F
2,886
Growing degree days, base 50°F
2,011
Growing degree days, base 55°F
1,279
Growing degree days, base 60°F
685

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,25500
February97600
March83901
April609017
May3522156
June9732387
July7130587
August2284527
September1749292
October547044
November87500
December1,21500

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 16.6 km from Bayfield. 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 USC00054254 (Ignacio 6ESE). Public domain.