I am making a cake for son's birthday tomorrow.   the plan was to ganache the cake and cover with fondant.   I find dark chocolate too rich for little mouths, so I used milk chocolate for the ganache.  I stupidly did not think to check the quantities of cream for milk chocolate as against dark chocolate BEFORE I made the ganache - so I used ratio of 2:1 instead of 3:1.  I spread the ganache on the cake last night, and this morning, the ganache is still soft to the touch - you can easily spread it (with dark chocolate by this stage you would need a hot knife to spread it).

Would anybody know if I am able to still use fondant over this?

It is too late to start again ... and I imagine my son will be upset if he doesn't get his themed cake. 

And just to make matters worse ... we will have rain today with 30 degree C heat. 

I would appreciate any advice.  I don't want to go covering the cake with the fondant if in the end it will just fall off or go funny.

Thanks!

AYou can put fondant over a soft ganache, just as you would over buttercream.

thanks brandisbaked!  I am a little relieved.