transfer dude

Formal recruitment happens in the spring, which every house participates in, and informal happens in the fall. "Every house" also participates in fall rush, but I'd say only about half off them actually take a pledge class then. It really depends on the house, but ones with bigger PCs will just wait until spring, while the ones with fewer pledges each rush will give out bids both semesters.

On one hand, a lot of frats tend to prioritize freshman over sophomores because they'll be in the house longer, but on the other it helps a lot if you already know a few guys in all the houses you're interested in. I would rush in the spring as a freshman transfer, and see how you do. If you don't get a bid or aren't crazy about the houses that did give you one, try again in the fall and following spring and see what happens. It's better (in general) to rush early and try again later than just wait.

Freshmen tend to be prioritized over sophomores, transfer or not. In general, if a house isn't taking sophomores in the fall, you can expect them to be unlikely to take sophomores in the spring. That's not to say its impossible, its just less likely, but certainly does happen. For that reason, it would be unreasonable not to rush in the fall on the sole basis of fewer houses taking pc's.