DS is 16 months and has always been a good sleeper (that's karma for the (non) sleep habits of his sister).
He now sleeps 12-13 hours a night and has 2-3 naps a day, mostly totalling about 3 hours (sometimes more, rarely less. He gets up between 7 and 8 and is generally asleep again by 9... plays havoc with our social life!
I know I'm probably stressing over nothing but it seems like such a lot of sleep. It isn't related to the current temperatures but he really does need to have this sleep
FWIW, he is developing perfectly in every other way.