How to check hourly weather for next day on iphone 4?

How do i check the hourly weather for tomorow on my iphone 4 on the weather app that cones with it

It's not possible from within the app - you can see the next 10 hours (I'm sure you couldn't see that far pre IOS 6?).

There are lots of weather apps on the app store though - or you could find your favourite weather web site and add it to the home screen (in safari, click on the little box at the bottom with an arrow, then click add to home screen).