Remember back when waking up was like this every morning? (work safe, but put on your headphones)
Yeah, that was before you had kids. Five (5!) emails in the past two weeks from people whose kids are waking up between 4:30 (shoot me now) and 5:30 every day. I know this is not a new problem, and we've tossed at around a bunch of times in the past, but it does seem to me that it goes in cycles. Three of the five emails I got were from parents of 7-month-olds. And we're having wacky weather all across North America at least (torrential rains, snow in June, or blazing heat waves, depending on where you are on the continent).
I'm going to hypothesize that it's the combo of age (and where your kid is at in the timeline of developmental spurts, growth spurts, physical milestones, and teething), personality, and the change of seasons/weather.
I think there are all sorts of things you can try to stop the early waking. One of them might work*. Or none of them will work.
I think, like anything else having to do with sleep, that one of two things is true:
a) It's a phase, and like all other annoying phases, it'll pass. So you need to figure out how to deal with it until it passes.
b) Your kid is hard-wired to wake up early. In that case, you need to figure out some way to work around that until your kid is old enough that they can wake up early and amuse him/herself and it won't be dangerous.
I think a) is far more likely, although I know some adults who can't seem to sleep past 5:30 no matter what, so it's probably just a personality thing for a certain segment of the population. In any case, it's time-delineated in that you won't have to deal with it forever.
Take some deep breaths, talk to your partner about working out some sort of schedule so neither of you takes the hit all the time (and both of you never take the early-rising hit together), assess exactly how much your kid needs from you in the morning (if your kid wakes up but it just happy playing alone in the crib or bed you don't actually need to be awake for that), and know that the day will come when you'll have to pry your child out of bed in the morning with a crowbar. I hear.
Oh, and just so you know I'm feeling it, too, I was wakened at 5:35 and then 5:50 this week by my younger one. After the second time, I told my older son that they weren't allowed to come out of their room until 7 am except to go to the bathroom. It worked once. I'll keep you posted about any future success.
* The top-rated things readers recommend: black-out shades (that you buy or make from black-out fabric you can buy at fabric stores, or cardboard over the windows at night), changing the temperature of the room, checking to see if there's some sort of noise that happens at that time of day (neighbor starting a car to go to work, loud dog, etc.) that's causing the waking, and bumping bedtime earlier by 30-60 minutes (yes, it's counterintuitive).