Its actually easy to find housing anytime because there are soooo many apartment complexes here, but you might have to live with people you don't know which could be scary if they turn out to be non-stop partiers and you're trying to study.
Apartment complexes to stay away from if you're looking for quiet/nonundergrad housing:
Fountain Circle (Where I live, next to the marketplace, it is along the G bus line which runs the most often, every 15 minutes I think. However, people here, including me, are pretty loud and there are often large parties on the weekend.)
Same general deal for the Lexington and Arlington farm apartments.
But if you need info, look here:http://www.daviswiki.org/Apartments
The wiki has allllll sorts of stuff about Davis, I mostly use it to figure out if food places are still open when I get late night cravings though.