Davenport climate

Davenport Frost Dates and Growing Season

NOAA 1991-2020 normals for Davenport, 0.9 km from Davenport, elevation 2369 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Davenport. 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 June 6 and the first fall freeze around September 11, a growing season of about 94 days.

Median at 32°F
last June 6, first September 11
Median at 28°F
last May 11, first September 27

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°F–––––––––
32°FJul 5Jun 24Jun 17Jun 12Jun 6Jun 1May 27May 20May 13
28°FJun 2May 25May 19May 14May 11May 7May 4Apr 30Apr 26
24°FMay 10May 5May 1Apr 28Apr 25Apr 22Apr 17Apr 12Apr 1
20°FApr 27Apr 19Apr 12Apr 3Mar 29Mar 22Mar 16Mar 10Mar 4
16°FMar 28Mar 17Mar 11Mar 7Mar 3Mar 1Feb 27Feb 22Feb 14

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°F–––––––––
32°FAug 26Sep 1Sep 4Sep 7Sep 11Sep 14Sep 18Sep 22Sep 28
28°FSep 9Sep 15Sep 20Sep 23Sep 27Oct 1Oct 3Oct 6Oct 11
24°FSep 27Oct 1Oct 3Oct 6Oct 8Oct 12Oct 16Oct 21Oct 29
20°FOct 5Oct 10Oct 14Oct 18Oct 22Oct 26Oct 30Nov 5Nov 13
16°FOct 17Oct 24Oct 28Nov 1Nov 5Nov 11Nov 16Nov 21Nov 27

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°F847568625752474134
32°F1261141081009488827666
28°F160154147141137131124117106
24°F194183177171167162157152145
20°F241230221213207198191183170
16°F276267259253247242235228218

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
7,662
Cooling degree days, base 65°F
207
Growing degree days, base 40°F
3,321
Growing degree days, base 45°F
2,361
Growing degree days, base 50°F
1,574
Growing degree days, base 55°F
949
Growing degree days, base 60°F
495

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22500
February1,00400
March87401
April644019
May4084124
June23518243
July8386468
August8285469
September27115219
October651030
November95300
December1,23400

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 0.9 km from Davenport. 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 USC00452007 (Davenport). Public domain.