The weather data includes the following:
   Month Day Year High Low Liq. Snow Depth

Month: 1 (Jan) through 12 (Dec)   Day: Day of Month   Year: 1918-present

High: High Temperature for the Day in Fahrenheit   Low: Low for the Day

Liquid: Amount of liquid precipitation that fell that day, measured in inches.
A reading of T for liquid indicates a trace (less than 1/100 of an inch).

Snow: Amount of snow falling that day measured in inches.
For snow, T (trace) means less than 1/10 of an inch.
Depth: Snow on ground in inches, which includes snow not melted from previous days.

Missing Data: "-" indicates the extreme rare case of missing data. In the rare case where the Franklin Institute does not have data for that day, an attempt is made to fill in the data from another weather station in Philadelphia.

If you compare with other data from Philadelphia, you may find slight variations due to the actual location the measurements were made. From 1999 to present, temperatures are daily from midnight to midnight while precipitation and snow are taken from 9 am to 9 am.