Hudson climate

Hudson Frost Dates and Growing Season

NOAA 1991-2020 normals for Maynard 2, 11 km from Hudson, elevation 205 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Maynard 2. 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 2 and the first fall freeze around October 6, a growing season of about 156 days.

Median at 36°F
last May 13, first September 27
Median at 32°F
last May 2, first October 6
Median at 28°F
last April 21, first October 18

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 27May 22May 19May 16May 13May 10May 7May 4Apr 30
32°FMay 16May 12May 8May 5May 2Apr 30Apr 27Apr 24Apr 22
28°FMay 5Apr 30Apr 26Apr 23Apr 21Apr 18Apr 15Apr 12Apr 8
24°FApr 20Apr 16Apr 12Apr 9Apr 6Apr 5Apr 3Apr 1Mar 28
20°FApr 8Apr 3Apr 1Mar 31Mar 29Mar 26Mar 23Mar 18Mar 14
16°FMar 31Mar 27Mar 24Mar 21Mar 17Mar 14Mar 12Mar 9Mar 5

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 14Sep 18Sep 22Sep 24Sep 27Sep 29Oct 1Oct 4Oct 8
32°FSep 25Sep 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 16Oct 22
28°FOct 2Oct 6Oct 10Oct 14Oct 18Oct 22Oct 25Oct 30Nov 3
24°FOct 14Oct 21Oct 26Oct 29Nov 1Nov 3Nov 5Nov 9Nov 14
20°FOct 30Nov 2Nov 5Nov 9Nov 12Nov 16Nov 18Nov 23Nov 29
16°FNov 10Nov 15Nov 19Nov 23Nov 26Nov 29Dec 2Dec 5Dec 12

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°F154148144140136133129124119
32°F174168163159156152148144137
28°F199191187182178174169165157
24°F223216212208205201197191184
20°F251243238233229225220215209
16°F273266260256252247243238232

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
6,216
Cooling degree days, base 65°F
729
Growing degree days, base 40°F
5,004
Growing degree days, base 45°F
3,864
Growing degree days, base 50°F
2,872
Growing degree days, base 55°F
2,016
Growing degree days, base 60°F
1,300

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20901
February1,02901
March895011
April523477
May21736296
June50136536
July4269730
August12212665
September11367406
October4165126
November716023
December1,03202

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 11 km from Hudson. 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 USC00194580 (Maynard 2). Public domain.