Right, with durations as you described, your layout should be displayed for 15s (the longest duration) and then whole layout should reload - or move to another layout if you’ve scheduled other layouts as well.
Perhaps have a look here:
Understanding Media Duration and how it affects the playback of a Layout
That’s because you do not need to edit anything there if you’re using Spring Signage cloud hosting.
Normally you’d need to register with darksky and get the API key which you’d then enter on the modules page to start using weather widget, but with our cloud hosting it’s all done and pre-configured for you.