I've had decent luck with the Met Office app for Android The weather is only at 1hr intervals but the rain radar maps are at 15min and you get the last 6 hours

I've had decent luck with the Met Office app for Android The weather is only at 1hr intervals but the rain radar maps are at 15min and you get the last 6 hours and the next 24, so you can see where patches of rain are coming from and where they're going to be at which time