Erica's Answer:
The south side of the street has houses facing north, and the opposite is true on the north side of the street. So, the people across the street from you on the north side have houses that face south. Sunlight comes to Philadelphia from the south, which is why you'll see a shadow on the north side of a building and lots of sun hitting the south side of the building. The sunshine heats the south-facing structure more than the north-facing structure, so the snow melts more quickly!- Erica
