Anna climate

Anna Frost Dates and Growing Season

NOAA 1991-2020 normals for Sidney 1 S, 14 km from Anna, elevation 940 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sidney 1 S. 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 April 27 and the first fall freeze around October 20, a growing season of about 175 days.

Median at 36°F
last May 5, first October 8
Median at 32°F
last April 27, first October 20
Median at 28°F
last April 16, first October 31

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 19May 15May 11May 8May 5May 3Apr 30Apr 27Apr 22
32°FMay 12May 6May 3Apr 30Apr 27Apr 23Apr 20Apr 17Apr 12
28°FMay 2Apr 27Apr 22Apr 18Apr 16Apr 12Apr 9Apr 5Apr 1
24°FApr 19Apr 14Apr 9Apr 5Apr 2Mar 31Mar 28Mar 24Mar 19
20°FApr 6Apr 2Mar 31Mar 27Mar 24Mar 21Mar 17Mar 13Mar 8
16°FMar 31Mar 24Mar 20Mar 16Mar 13Mar 10Mar 7Mar 2Feb 24

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 25Sep 29Oct 2Oct 5Oct 8Oct 10Oct 13Oct 17Oct 22
32°FOct 5Oct 10Oct 14Oct 18Oct 20Oct 23Oct 26Oct 29Nov 2
28°FOct 17Oct 23Oct 26Oct 29Oct 31Nov 1Nov 4Nov 7Nov 12
24°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 21Nov 26
20°FNov 7Nov 11Nov 15Nov 19Nov 22Nov 26Nov 30Dec 4Dec 10
16°FNov 15Nov 22Nov 26Nov 30Dec 4Dec 8Dec 12Dec 19Dec 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°F174168163159155152148143137
32°F194188184180175172168163156
28°F216209204201197193190185177
24°F242235229225220217213208201
20°F268259253248243239235229222
16°F292283276272267261256250243

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
5,911
Cooling degree days, base 65°F
817
Growing degree days, base 40°F
5,389
Growing degree days, base 45°F
4,206
Growing degree days, base 50°F
3,156
Growing degree days, base 55°F
2,238
Growing degree days, base 60°F
1,458

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20403
February1,00004
March824130
April4567119
May18458352
June28179602
July3257719
August8206663
September8995458
October37514171
November711031
December1,03105

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 14 km from Anna. 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 USC00337693 (Sidney 1 S). Public domain.