Melrose climate

Melrose Frost Dates and Growing Season

NOAA 1991-2020 normals for Melrose, 0.7 km from Melrose, elevation 4599 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 April 17 and the first fall freeze around October 26, a growing season of about 190 days.

Median at 36°F
last April 28, first October 17
Median at 32°F
last April 17, first October 26
Median at 28°F
last April 5, first November 4

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 9May 5May 2Apr 30Apr 28Apr 26Apr 23Apr 20Apr 16
32°FApr 30Apr 27Apr 22Apr 20Apr 17Apr 14Apr 11Apr 7Apr 1
28°FApr 22Apr 16Apr 11Apr 8Apr 5Apr 2Mar 30Mar 25Mar 17
24°FApr 9Apr 4Mar 31Mar 26Mar 22Mar 17Mar 13Mar 8Mar 3
20°FMar 28Mar 21Mar 16Mar 12Mar 8Mar 5Mar 1Feb 24Feb 17
16°FMar 15Mar 9Mar 4Feb 28Feb 24Feb 18Feb 12Feb 3Jan 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°FOct 2Oct 7Oct 11Oct 14Oct 17Oct 19Oct 22Oct 25Oct 29
32°FOct 13Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 4Nov 7
28°FOct 22Oct 27Oct 30Nov 2Nov 4Nov 6Nov 10Nov 13Nov 17
24°FOct 30Nov 4Nov 7Nov 10Nov 13Nov 16Nov 19Nov 22Nov 26
20°FNov 7Nov 13Nov 17Nov 20Nov 23Nov 26Nov 29Dec 3Dec 9
16°FNov 17Nov 23Nov 27Dec 1Dec 5Dec 9Dec 14Dec 19Dec 26

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°F187181178174171167163159153
32°F210203198194190186182178171
28°F233226220216212207203197190
24°F259251245239234230226220213
20°F284275267262258254249243234
16°F318306297292287282275267258

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
3,621
Cooling degree days, base 65°F
1,501
Growing degree days, base 40°F
7,316
Growing degree days, base 45°F
5,811
Growing degree days, base 50°F
4,476
Growing degree days, base 55°F
3,315
Growing degree days, base 60°F
2,329

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January783010
February601025
March4451111
April21917266
May58129538
June1339787
July0423888
August0380845
September22187615
October19725309
November518171
December778012

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 0.7 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 USC00295617 (Melrose). Public domain.