Rock Port climate

Rock Port Frost Dates and Growing Season

NOAA 1991-2020 normals for Auburn 5 Ese, 20 km from Rock Port, elevation 930 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Auburn 5 Ese. 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 24 and the first fall freeze around October 10, a growing season of about 167 days.

Median at 36°F
last May 1, first October 1
Median at 32°F
last April 24, first October 10
Median at 28°F
last April 15, first October 20

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 15May 9May 6May 3May 1Apr 29Apr 27Apr 24Apr 19
32°FMay 6May 2Apr 29Apr 27Apr 24Apr 21Apr 18Apr 15Apr 10
28°FApr 28Apr 24Apr 21Apr 18Apr 15Apr 13Apr 9Apr 6Apr 1
24°FApr 21Apr 16Apr 12Apr 9Apr 6Apr 3Mar 31Mar 27Mar 20
20°FApr 12Apr 7Apr 3Mar 31Mar 27Mar 23Mar 19Mar 15Mar 9
16°FApr 4Mar 30Mar 25Mar 20Mar 17Mar 13Mar 10Mar 5Feb 28

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 18Sep 22Sep 26Sep 29Oct 1Oct 3Oct 6Oct 9Oct 14
32°FSep 25Sep 30Oct 3Oct 7Oct 10Oct 13Oct 15Oct 19Oct 23
28°FOct 6Oct 10Oct 14Oct 17Oct 20Oct 22Oct 25Oct 28Nov 2
24°FOct 15Oct 20Oct 23Oct 26Oct 29Nov 1Nov 3Nov 6Nov 11
20°FOct 24Oct 30Nov 2Nov 4Nov 6Nov 10Nov 13Nov 17Nov 23
16°FNov 2Nov 6Nov 10Nov 13Nov 16Nov 20Nov 24Nov 28Dec 3

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°F167162158154151147143137131
32°F186180175171167164159155148
28°F206199193190186182178173166
24°F227219214209205201197191185
20°F248241235230225220216211204
16°F269261255250245240236229221

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
5,801
Cooling degree days, base 65°F
1,256
Growing degree days, base 40°F
6,044
Growing degree days, base 45°F
4,844
Growing degree days, base 50°F
3,766
Growing degree days, base 55°F
2,808
Growing degree days, base 60°F
1,970

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,25800
February1,00005
March736349
April38715166
May124103451
June9273714
July1380843
August5309769
September76148524
October35125212
November740133
December1,11402

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 20 km from Rock Port. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00250435 (Auburn 5 Ese). Public domain.