Melbourne climate

Melbourne Frost Dates and Growing Season

NOAA 1991-2020 normals for Calico Rock 2 Wsw, 23.6 km from Melbourne, elevation 350 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Calico Rock 2 Wsw. 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 14 and the first fall freeze around October 28, a growing season of about 196 days.

Median at 36°F
last April 25, first October 17
Median at 32°F
last April 14, first October 28
Median at 28°F
last April 1, first November 5

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

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 6Oct 11Oct 14Oct 17Oct 19Oct 22Oct 25Oct 28
32°FOct 12Oct 18Oct 21Oct 25Oct 28Oct 30Nov 1Nov 4Nov 8
28°FOct 24Oct 29Nov 1Nov 2Nov 5Nov 7Nov 11Nov 15Nov 23
24°FNov 2Nov 6Nov 10Nov 13Nov 16Nov 20Nov 25Nov 30Dec 5
20°FNov 10Nov 16Nov 21Nov 25Nov 30Dec 3Dec 7Dec 12Dec 21
16°FNov 22Nov 29Dec 3Dec 8Dec 14Dec 20Dec 24Dec 30Jan 7

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°F192185181178174169166162156
32°F215209204200196192188183176
28°F244235229223219214210205198
24°F264257252247243238234228219
20°F291283276271266260255249241
16°F324314306299293286280273262

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
4,227
Cooling degree days, base 65°F
1,207
Growing degree days, base 40°F
6,658
Growing degree days, base 45°F
5,264
Growing degree days, base 50°F
4,023
Growing degree days, base 55°F
2,930
Growing degree days, base 60°F
1,992

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January918112
February730020
March553382
April27517225
May9082459
June5236681
July0355820
August1337801
September39148560
October23925274
November547272
December831017

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 23.6 km from Melbourne. 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 USC00031132 (Calico Rock 2 Wsw). Public domain.