For those of us in the northern hemisphere, it's getting cold! Might explain the drop in participation.
I'm still assembling my winter biking gear but so far we've gotten down to ~30F and I've been just fine. I am nervous about black ice & slippery road conditions (especially in the moderately cold, freeze-and-thaw type of winter we tend to have where I live). But even if I only bike on dry days, it's still better than nothing...