scrubber3
Not really here
Rain water drains out of the inlet via the outer slits near the top. No need for a drain hole unless you can make a one way valve just for a piece of mind. Or if you think you really need it as YMMV. 
The only time I turn mine around is when it snows heavy as snow can get packed in there as I found out first hand.
The only time I turn mine around is when it snows heavy as snow can get packed in there as I found out first hand.