Plant Hardiness Ratings ?

The RHS has a hardiness rating system for plants . This ranges from H1 (very tender ) to H7 ( very hardy). For example Sweet Peas are H5 , meaning they can go outside in March , Petunias would be H2 , meaning only plant out from the middle of May.
Last year I found a couple off sites showing the "H" level for most off my annuals . I can't locate any info on this now , any ideas ?
TIA

 

Is it not on the RHS website?

 

Is this what you are after

https://www.rhs.org.uk/about-the-rh.../2013-issues/february/How-hardy-are-my-plants

 

Thanks but that is the page I was referring too. It does explain the H hardiness system , but I was looking for a page which gave the H rating for various family of plants . I found one last year but can't find one now ?

 

Ah sorry i miss understood i will give google a go and see if anything comes up for me