These are the random things that pop into my head:
When Smallville would first start filming for a new season, they would usually start sometime in July, right? Aqua was the 4th episode of the 5th season. It probably would have been filmed in late July, early August...Would it have already been that cold during that time in Vancouver that the cast would need to be in sweatshirts & pants inbetween scenes? Just curious....
Is my timing off?
Exhibit A
Exhibit B