S.L.
It is not uncommon for fevers to spike at night; ussually if a fever runs more than three days, the peditrian will want to know. Of course keep an eye on his energy level, appetite, and any other symptoms he may be having. He could also be teething (if he hasn't got his second set of molars yet), but fevers associated with that are ussually lower. I know a lot of respiratory and ear infections have been going around. If he has a fever again tonight, I would reccomend calling the Ped; they may want to see him.
S.