Bird Island climate

Bird Island Frost Dates and Growing Season

NOAA 1991-2020 normals for Olivia 3E, 2.7 km from Bird Island, elevation 1100 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Olivia 3E. 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 6 and the first fall freeze around October 1, a growing season of about 146 days.

Median at 36°F
last May 15, first September 21
Median at 32°F
last May 6, first October 1
Median at 28°F
last April 27, first October 10

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°FMay 28May 24May 21May 17May 15May 13May 10May 6May 3
32°FMay 20May 15May 12May 9May 6May 4May 1Apr 29Apr 23
28°FMay 10May 5May 2Apr 30Apr 27Apr 24Apr 21Apr 16Apr 12
24°FMay 1Apr 26Apr 23Apr 20Apr 17Apr 13Apr 10Apr 6Apr 2
20°FApr 22Apr 18Apr 13Apr 10Apr 7Apr 4Apr 2Mar 29Mar 22
16°FApr 15Apr 9Apr 5Apr 3Mar 31Mar 27Mar 23Mar 19Mar 13

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 21Sep 25Sep 27Oct 1Oct 5
32°FSep 15Sep 20Sep 25Sep 27Oct 1Oct 3Oct 6Oct 9Oct 14
28°FSep 24Sep 29Oct 3Oct 6Oct 10Oct 13Oct 16Oct 20Oct 25
24°FOct 4Oct 11Oct 15Oct 19Oct 21Oct 24Oct 27Oct 31Nov 4
20°FOct 16Oct 21Oct 25Oct 29Oct 31Nov 2Nov 5Nov 8Nov 13
16°FOct 26Oct 31Nov 3Nov 6Nov 8Nov 11Nov 13Nov 17Nov 20

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°F147141137132129125121116109
32°F164158152149146143139134127
28°F185179174169165161157153146
24°F208201195191187183178172165
20°F226218213209205201197192187
16°F242234229224220216212207200

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
8,436
Cooling degree days, base 65°F
513
Growing degree days, base 40°F
4,248
Growing degree days, base 45°F
3,269
Growing degree days, base 50°F
2,403
Growing degree days, base 55°F
1,646
Growing degree days, base 60°F
1,009

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,65200
February1,37300
March1,12606
April648148
May28830246
June55121516
July15185635
August37125553
September19346318
October580475
November1,01104
December1,45800

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 2.7 km from Bird Island. 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 USC00216152 (Olivia 3E). Public domain.