He will have tantrums for some time to come yet (sorry!) and what he's doing, although not desirable, is all normal for his age group. It sounds like you are responding in a very good way, but try to do the same thing each time so he gets the message loud and clear and be sure he's not getting even the tiniest bit of attnntion while he's yelling. Make sure he gets a cuddle straight after a tantrum as calming down is a skill worth praising Is his sister older or younger? If older, try not to compare what he does to what she did as that only makes us worry and they all get there in the end.