Android 6 (Marshmallow) introduced a new secuirty permissions model. This means every app has to specifically ask for permission to access to resources. If you open up the settings app, it will prompt you allow access. Click on 'Allow' when this appears.
This can be fixed by either:
1. Ensuring Location is enabled in the phone settings and either "GPS, WIFI & Mobile Networks" or "Wifi & Mobile Networks" is selected as the Locating Method
2. Setting a manual location through the companion app.
Settings can be changed by going to Google Wear on your phone, selecting the watch face and selecting the gear icon. This will display a summary of the weather information. From here you can select 'Settings' from the menu. You can customise the look of your watch face, from 12 or 24 hour mode, date formats, colours and displayed elements.
Ensure you have connection to the internet to download the latest weather information
Weather information is supplied by OpenWeatherMap
OpenWeatherAPI combines Weather information from a number of different sources, including Commercial Suppliers and Amateur Weather Stations. This means that Weather displayed on the watch face can be from one of these Amateur stations and closer to your location than one of the commercial, City wide Average stations.
We're currently investigating other providers of Weather Information, however the subscription based model these often employ mean that they are cost prohibitive for us.