Waking early but back to sleep...why?

Michaela

my boy is over 1 year old now.His schedule usually is:

6.20 wake up

9.20-10.00 1.nap

1.30-3.00 2.nap

6.45/7.00 bedtime

He sleeps quite well during the night but then he starts waking up around 5am (which is too early for us) , so I grab him and rock him back to sleep.It usually works and he fall asleep until 6.20 for our normal wake up. Not sure why he does it? I was thinking is it sign he is overtired? i woudl love to if he would sleep straight until 6.20😒Sometimes it doesnt work and he fights it and doesnt go back to sleep but he is so tired that he could sleep at 6 already😒any ideas how to fix it?