Weather app shows identical wrong information for all cities except current location.

The weather app in my iPhone 6 shows the correct information for my 'current location'. However for all the other cities it shows seemingly random information (including current temp/conditions and forecast), which is identical for all the other loaded cities. For example right now it's 17C in Revelstoke, BC (my current location), but it's 24C in Calgary, Toronto, Muscat, Oman, London, Dublin, Vancouver; all with identical conditions and forecasts. I'm just passing through Revelstoke, but when I'm in a city that I have loaded for it to show the weather, it will show as the correct weather under the current location page, but different incorrect weather that's the same as all the other cities on it's own page.

I've tried phone restart and reset, didn't work. This is the native iPhone

app, so I can't delete it and reload. This is not a big problem when I'm at home, but renders the app useless when

I'm travelling for seeing the weather in any place other than my current location. Any help would be much appreciate. Thanks.