My 27 does the same thing in winter. After the temp drops below 60 and it rains I always get water in the bilge. It's bone dry all summer.
I've been chasing leaks for the last couple of years and the amount of water I get has diminished but I still can't find where it is coming from (but i've narrowed it down to the cockpit area).
I'm not too familiar with the 310 but check the archives, there may be some insight on areas prone to leaking for that model. Check the obvious stuff first, for example loose or misaligned hatch boards, a port or hatch not fully closed, maybe a lazarette that wasn't closed properly, etc. A couple of weeks ago I went down to discover a bunch of soaked cushions - all due to a little piece of dirt on the gasket of a port.
Manny