yesterday in the afternoon i noticed that the snow is melted off the top on my garage, but not my neighbors'.
none of us have heated or insulated garages, so there's no heat to be escaping through the roof, in theory at least.
the best idea i can come up with for why this happened is that i regularly park my car in my garage and my neighbors do not.
this means that yesterday i opened and closed my garage door twice at the warmest part of the day, allowing in warm air to settle underneath the roof, so maybe the lack of melted snow on my neighbors' garages is about an undisturbed closed pocket of cooled air.
still, my door wasn't open all that long; just long enough to get the car in and out, so if that much air disturbance makes a difference, that's kind of impressive.