How do I change the Weather forecast and clock on the 'Dashboard'?

Finally bought into the 'all things apple' gadgit man theme.... Never used Mac laptop so all the little things suddenly very difficult!

Using 'mission Control to access the 'dashboard' (or 3 finger sweep I just learnt!!) but the weather is showing a place called Cupertino (never heard of it but it is clearly a lot hotter than here!) and the time says Amsterdam!

How do I change it please?