Weather app issues: iPhone 4S iOS 7

I no longer seem to be able to add locations to the built in weather app, since updating to iOS 7.

Any location i type, i get the "validating city..." message, then the "no results found".

I have tried rebooting iPhone, cycling wifi and mobile data, closing app etc. nothing seems to work.

This happens whether i use a city name, a post code, or an airport.

Any help would be much appreciated.

Thanks,

James