This is a new plugin and I am still tightening the integration with the mobile app (more to come on this in the next update). The weather shown in the mobile app is separate than the OSPi weather plugin source (weather plugin vs weather provider in settings page). This will be changed in the next update to use the OSPi information when provided rather than the mobile app settings.
As you noticed it uses the location set via the device options page.
The plugin outputs it’s status to console. The plugin uses the rain delay setting to execute its stop and therefore will be noticed as a rain delay in the mobile app when activated.