Why does he only talk to me late at night?

So I've been talking to this guy for a couple of weeks now, and we have been flirting a little. We mainly Snapchat, but he ONLY responds or talks to me at 11:00 PM or later until 3 or 4 AM. I know he's on his phone during the day because he posts to social media. He has also mentioned hanging out before but says he just wants to stay at his house and "chill" and not go out anywhere. What does this mean? Why does he only talk to me so late?
Why does he only talk to me late at night?
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