Melrose climate

Melrose Frost Dates and Growing Season

NOAA 1991-2020 normals for Melrose, 0.5 km from Melrose, elevation 1195 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Melrose. 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 4 and the first fall freeze around October 1, a growing season of about 148 days.

Median at 36°F
last May 14, first September 23
Median at 32°F
last May 4, first October 1
Median at 28°F
last April 26, first October 12

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 29May 25May 21May 17May 14May 11May 8May 5May 1
32°FMay 19May 13May 10May 7May 4May 2Apr 30Apr 27Apr 22
28°FMay 8May 4May 1Apr 29Apr 26Apr 24Apr 21Apr 17Apr 13
24°FApr 30Apr 26Apr 23Apr 20Apr 17Apr 15Apr 12Apr 9Apr 5
20°FApr 22Apr 18Apr 14Apr 11Apr 8Apr 6Apr 4Apr 1Mar 27
16°FApr 16Apr 11Apr 7Apr 4Apr 2Mar 31Mar 27Mar 23Mar 18

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 11Sep 14Sep 18Sep 20Sep 23Sep 26Sep 28Oct 1Oct 5
32°FSep 17Sep 22Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 15
28°FSep 27Oct 1Oct 4Oct 8Oct 12Oct 14Oct 18Oct 22Oct 26
24°FOct 4Oct 11Oct 15Oct 19Oct 22Oct 26Oct 29Nov 1Nov 5
20°FOct 17Oct 23Oct 27Oct 30Nov 1Nov 3Nov 6Nov 10Nov 14
16°FOct 26Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 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°F148142138134130126122117111
32°F165159155152148144140135129
28°F186180175171166162158154148
24°F207200195190187183179173166
20°F225218214210206202198192184
16°F241234229225221217213208202

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
8,811
Cooling degree days, base 65°F
483
Growing degree days, base 40°F
4,096
Growing degree days, base 45°F
3,147
Growing degree days, base 50°F
2,305
Growing degree days, base 55°F
1,575
Growing degree days, base 60°F
961

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,71100
February1,42800
March1,17304
April692033
May31025224
June63106494
July15184634
August35131561
September21436290
October617262
November1,05203
December1,50200

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 0.5 km from Melrose. 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 USC00215325 (Melrose). Public domain.