Posted by Phil in Atlanta
on 11/7/2009, 7:26 pm, in reply to "38 in my backyard but 32 at the airport last night"
99.26.112.230
Hi Tom - just wanted to clarify frost vs freeze.
According to this article below, frosts are generally getting later each year and even the airport hasn't had a frost before Halloween since 1992. That said, they note at the turn of the last century, the average frost date was Nov 17.
I believe the article was referring to freezes, not frosts. 2 separate events (usually).
And it said, "During a 15-year stretch at the turn of the century, for example, the average first freeze date was Nov. 17." Sounds like a nice run indeed - as well as the noted recent relatively warm period, "October freezes used to be routine, but the airport temperature hasn't dropped to 32 before Oct. 31 since 1992, the longest such streak in the 136-year period of record."
Generally 36F is considered a frost temp (but this various widely). I guess the thought is that at 36F frost can definitely occur. (but some have noted frosts at 40F, and others (especially out west) have noted little frost even at freezing.
Below are the official Philly numbers in case you are interested. Glad you escaped the freeze/frost. Sorry about game 6.
Phil
Just looked this up. Per NOAA/NWS site, here is a 30 year average (1971-2000):
Philadelphia Area (ThreadEx Station)
First/Last Dates
Minimum Temperature <= 32 degrees F
Years: 1971-2000
Last First
Prob 100% 100%
Average Apr 6 Nov 4
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Philadelphia Area (ThreadEx Station)
First/Last Dates
Minimum Temperature <= 36 degrees F
Years: 1971-2000
Last First
Prob 100% 100%
Average Apr 15 Oct 26
Atlanta, Georgia
January 52F/34F, July 89F/71F
Hardiness z8a
Annual: Rain = 50 inches, GDD's = 5300
Winter low last 6 years: 12F, 15F, 18F, 24F, 16F, 18F
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