Early morning wake ruining the whole nap schedule, 10 months

Chicken and egg, but usually at this age it's overtiredness creating a cycle, early wake leads to early/long naps which mess up sleep pressure for the next night which causes another early wake. We broke it by gently capping that first nap and pushing it 15 min later each day.

5am wakes are often a too-early bedtime OR too-late, frustratingly it can be either. What's her bedtime? We found pushing bedtime 15-20 min later actually fixed our 5am club situation. Counterintuitive but worth tracking for a week.

Check that the 5am wake isn't hunger driven, around 10 months some babies are genuinely getting hungry overnight or early. Also is the room truly dark at 5am? Summer light sneaking in destroyed our early mornings until we taped cardboard over a gap, ha.

We treated anything before 6am as night and kept it boring and dark, no getting up, no playing, until 6. Took about two weeks of consistency but the wake time drifted later. Be patient, the body clock is stubborn but it does respond.

19°C is good. I'd look at the first nap timing hard, if she's been awake 5+ hours by bedtime because the schedule shifted early, that overtiredness can trigger the 5am wake the next morning. Capping naps to protect bedtime helped us most.