Sure is cold in July in Philly

Fall leaves on the Wissahickon walk when recording the accident. Characters wearing coats. Lithgow's breath clearly visible (again wearing a coat) during the final scenes. Travolta still listening to the tape during snowfall, which wouldn't happen til Late Oct at the very earliest.
You'd think Travolta would have hypothermia after diving in that water.

Also, I know it was crazy in the early 80s and you could smoke on planes...but Travolta is smoking in a hospital too...lol

Having lived there, Lincoln drive where the accident happens is a busy road with lots of traffic and frequent accidents as its narrow lanes winds through hills and often are wet from water/ice runoff. And full of potholes to boot!

Great location for the scene though. It's a beautiful spot with the huge arch bridges over the valley.