The Schuykill River enters the region from the north and eventually forms the western bountry of what is generally considered Center City Philadelphia. The Schuykill River then runs into the Delaware River in South Philadelphia near the Philadelphia International Airport.
Elevation in the entire region ranges from at or near sea level to just a few hundred feet above. The Appalachian Mountains to the West, the two rivers and the Atlantic Ocean just 50-60 miles to the east all have a moderating effect on the region's climate.
The regions weather is highly unpredictable. Most winters are generally cold but not sub-freezing. Some winters see very little in the way of snow. Others seem to feature one snowstorm after another. Generally, heavier snow is seen to the north and west of the city with less snow in the city itself and the New Jersey suburbs.
Summers tend to be hot, but tolerable, unless the humidity is high, which often is the case in July and August. Spring and fall tend to be mild and the most enjoyable seasons of the year. Daily temperature averages range from a low of 23 degrees and high of 28 degrees in January, to a low of 67 degrees and a high of 86 degrees in July.
Rainfall is mostly spread out throughout the year, however, recent years have seen both an extended drought on one hand and weeks of almost daily rain on the other. Annual precipitation totals 41 inches, with between 6-9 days of precipitation per month.
Weather statistics c/o World Meteorological Organization