Something in the air maybe? DS (just two) has woken at 5.30 and 5.45 am the past couple of mornings. He used to be an early waker (5.30 was quite normal for him) but over the past few weeks has been getting later and later so it was usually between 6.30 and 7am, sometimes even after 7am (he goes to bed at 7pm)
He's happy enough to stay in his cot awake for 30-45 mins but he sings loudly so DP and I can't sleep through it.
Nothing's changed in his routine. We're going to try putting the heat on earlier to see if that helps but his room doesn't feel cold so I don't think that's what's waking him.