It seems so obvious but you'd be surprised how often this happens. Your selling a home (maybe you don't live there) and it snows. Please owners, you need to make arrangements to have the driveway and walks shoveled. An agent pulls up to your home with their customers only to realize they have to walk through 6 inches of snow to get to the front door.
Not only will the buyers probably pass on going in the house, but if they do go in, there will be a wet mess. And buyers out looking in the snow are probably "serious buyers"