|"Official" weather data for Philadephia (that is, data
that the National
Weather Service feels is reliable enough to be used in its
goes all the way back to 1872. That data is accessible, by
year, below. Clicking on the letter "G" under each year
accesses a graph of that year's daily high
and low temperature data. The data set in its entirety
(that is, not broken down by year) is also
At the bottom of the page, you'll find
that show yearly weather data for the Philadelphia region
back to the late 1800s.
The data files have seven columns:
In columns 6 and 7, the value -1 sometimes appears. This
stands for a "trace"
of precipitation, meaning that precipitation fell but it was
to be measured. For liquid precipitation (column 6), this
means less than
0.01 inches, while for snowfall (column 7), it means less
than 0.1 inches.
The value "-999" appears whenever data was not available or
was not observed.
Columns 1, 2 and 3 contain the month, day, and year.
Columns 4 and 5 are the daily high and low temperatures (in
Column 6 is the daily precipitation (rain plus melted snow),
of an inch. For example, 5 is .05 inches, 62 is .62 inches,
and 289 is
Column 7 is the daily snowfall, in tenths of inches. For
example, 3 means
..3 inches, 51 means 5.1 inches, and 107 means 10.7
The following charts also illustrate
in Philadelphia. The data used to create the charts is also available.