If I ask Siri "what is the weather in Hamilton", it gives me the weather for Hamilton, Canada. 

It’s a real shame. Apple seem to have been caught firmly on the back foot with this. 

Really the only reasons I’m still using iPhones are that my camera manufacturers don’t make their app for Android and all our computers are Apple. Also my wife likes iPhone so it makes communication easier via iMessage etc. 

I’m really not sure what’s going on in Cupertino these days but SJ would be appalled I feel. 

Behodar:

 

That doesn't look like what I did, so I'll need to retry at some point, and then possibly use your solution if it doesn't work.

 

I decided to test this on the way into work today. It's apparently the first time I've tried since updating iOS, because now I can't find the option to invoke Siri and ask for a song in the first place!

I thought I'd previously done it by pressing the "voice" button on the steering wheel, but it's invoking the car's own voice "feature" instead of Siri.

[Edit: The trick is to hold the button, not just press it. I can now request songs via Siri and it seems to work reliably.]