[ He makes a show of looking around, confused, and then turns around to beam at her innocently. ]

You sure the heat's not getting to you? Maybe you imagined it. I'm looking and I'm not seeing any - hey look, snow!

[ While he's talking he's casually had his arms crossed behind his head. At some point he palmed the snowball out of his hood and tossed it in an arc from behind his head, aimed squarely at the top of hers. ]