Having just got back from a very wet week in wales, some of the the best riding i've ever had . One mistake was not taking my northwave waterproof boots, but the wife likes riding  flats and 5-10's become very soggy very quickly riding down a CYB river even when it's not raining, waterproof socks are an option but you still need to dry out the shoes for the next days riding. So I'm looking for a lightweight non winter waterproof shoe/boot for flat pedals, any recommendations ?

i wear 5-10s with water proof socks, as long as the socks are clean and dry for the next ride it doesnt bother me if the shoes are still wet. can be a bit difficult to get on though when still wet..

2 pairs of flat 5-10s (or similar) 2 pairs of sealskinz socks and a pack of nappies to soak up the water. probably cheaper than waterproof boots. especially the nappies.

I've thought about using some dubbing on my old 5.10s for wet weather riding, it would still get down inside them tho but should keep the worst out of em. For the sealskinz try cutting the cuff of a latex glove and putting it over the top of the sock, that seals them up lovely. I was getting water running down inside them and then staying put in the sock, not nice.