What an interesting phenomenon you are documenting with this photographic technique. The surge of the flies, trying to escape the freezing cold. I never notice them trying to sneak into my apartment... but at some point during the fall season they stop buzzing around our patio and just leave us alone.
Yep. The autumn period has been a bit warmer than normal here, so the fly season has extended. But, it isn't too much of an inconvenience, though my daughter hates all bugs (unless they are cute).