Humans, like most mammals, are very sensitive to the local weather. They do not hibernate, but they restrict their activities greatly during the winter months. They spend the majority of their time in their dens; if they are outside, they are most likely moving from one den to another. Without any natural protection, they are forced to don thick layers of material to shield themselves from the elements; they bustle through the outside until they reach their destination.
While out-of-season humans are not terribly rare, they aren't terribly interesting either. In season humans, however, are fascinating. You have an opportunity to witness far more complex behaviors; their modes of play and a great deal of their social interaction become amplified. They gather in groups on just about any sunny and moderately flat area; tight little knots around the small little "shops" they create for nourishment, or around "parks" (preserves of other wildlife they encourage and use for recreation).
At any rate, it inspired me. I think it would be a worthy effort to try and observe this species more intently than I usually do. Since their activity levels are increased with the weather, it's certainly a good time to start investigating them; I also think that the general audience might be interested in some of the trivia about this complex and fascinating species.