Wednesday, November 28, 2012

Certainly Ain't Last November

A year ago today our high was 70 degrees. Since today is running about 25 degrees colder than that toasty Monday of a year ago, I thought it would be an intriguing trip in time to talk about the differences between this year and last year when it came to temperatures.

Our average high temperature through yesterday in Philadelphia is running 7.5 degrees colder this year than last year. For sake of comparison, November 2011's overall average of 51.3 degrees (high and low combined) was the 5th warmest on record.  We're running at 44.9 through yesterday and will probably finish up in the 44.2 to 44.4 range by month's end for an average temperature.   Instead of being one of the warmest Novembers going back to 1872 (when "official" climate data started getting record), this November will end up as the coldest November since either 1996 or 1997 in Philadelphia.

November 1997 (not shown in the graphic below) had an average temperature of 44.4 degrees. Getting down to 44.2 would tie us for 8th coldest since 1962 with November 1965.

The coldest November in the last 50 years and the 3rd coldest on record was in 1976 -- 39.9 degrees.  The two that were colder than 1976 occurred in 1873 and 1875.   Three of the ten coldest Novembers since 1872 (1996 is #6 on that list and 1962 is #9) make this list.

Those seven coldest Novembers listed above are a motley bunch -- some had great subsequent winters (1967-68 and 1995-96), some were very cold (1980-81 and 1976-77), one was pretty good on snow (1962-63), one was warm (1996-97), and one was mild and snowless (1972-73).

Despite this cold November, 2012 as a year will still end up as the warmest in Philadelphia unless December ends up colder than 33.7 degrees for a monthly temperature (which is 3.7 degrees colder than average).  With our likely warm start to December, that might be a tough task to accomplish.