Waking up too early crying

For the past couple of weeks, DS has been waking up on 6am on the dot, which is 30-60 minutes earlier than his usual wake up. He wakes up so unhappy, crying so hard. Its obvious he doesn't actually want to be awake, but we can't seem to get him to go back to sleep. We've tried bottles, cuddles, patting, a bit of controlled crying, but nothing seems to work. So we get him up and he is soooooo grumpy and overtired. Its clearly become a habit to wake at that time- its not even light yet, so I can't blame it on that. Argh, not sure what to do!!!!!! Anyone successfully come through this?

is he waking up cold ??? does he still wear night nappies ??? is he thirsty??

I knwo Jack went thru a stage like that , and his feet were cold even in summer... so we let him wear socks a few times and also he was thirsty thirsty he takes 2 no spill drink things to bed full of water... it did help just some ideas

Is he teething? My DS iswaking 5am every morning these days because of teething. Sooooo tired!