iPhone Weather Wallpaper Displays "Location Services is Off" - Solved
This followed iOS update (26.3). Solution was to reselect the wallpaper and do customize. This then prompted a permissions pop-up, on which I chose the required option.
I think the issue was because Weather Wallpaper did not previously have its own entry in the Location Services in Settings, so I did not see that it did not have the required permission. But now it does.
iPhone 15 Pro