Castiel hadn't expected to run into anyone tonight, either, but he found he wasn't too terribly surprised to see someone else there. People did all sorts of things Castiel didn't expect, if he was surprised by each and every thing they did, well. He'd be in a constant state of surprise.
He considered the offer for a moment, then shrugged. "Sure," he said, reaching for one. Beer didn't have much of an effect on him, he usually had to go for the stronger stuff for a buzz or drunkenness. But he liked beer from time to time.
"Why are you out here in the rain?" he asked, curious. He couldn't help himself.