@bruno.tanqueray
Is the tide for my GPS position or for a reference port?
Your phone sends your coordinates, but the forecast comes back for the nearest reference point in the tide dataset, and it’s that point’s coordinates and name that are pushed to the watch. If the reference point is within 50 km of you the widget may still label it with your own town, so the name you see isn’t proof the curve is for your beach.
What triggers a refresh?
Nothing on the phone: there’s no tide screen in the app and no background schedule. The watch asks for data when it needs it, and the phone answers only if it’s connected and nearby, so the practical trigger is “watch connected to phone”, not “open the widget”.
Is there a cache or a daily limit?
There’s a cache, but I don’t know about a limit: each fetch pulls about a week of data, and the app serves it until roughly two days of it are left, or until you move more than about 10 km. That’s probably why it fetches once and then appears to do nothing for a couple of days.
What’s the correct sequence?
Pair the watch, keep the app installed and allowed to use location all the time (not just “while using the app”), keep the watch connected, then open the tide widget on the watch. If you there’s no tide data after that, the two things worth ruling out first are background location permission and a location that has no usable tide data (eg something inland, like Lake Tahoe).
NB: I don’t work for Suunto; these are my own observations. Someone who works for Suunto can tell me I’m wrong, or delete my post if it over-shares.