Taking a look out of the window today I got to thinking, is there a pair of either shorts or trousers that are very waterproof but also well vented and breathable?

I find every pair of waterproof bottoms I've tried have tried to boil me in the bag.

well, shorts are inherently a lot more breathable than trousers!

I've got some Altura Extreme shorts from Merlin for 50 quid that are very good.

I have endura venturi 3/4 length which are expensive £90-100 but are good.

I dont get the point, all waterproof stuff is boil in the bag if you actually put any effort in, fair enough the high end stuff will allow you to dry out a bit faster if you stop, & I know it ruins the mid ride photo of your bike at the top of a hill, but mudgaurds just work. Cheap too.

Hit the tag, otherwise the Altura attack 2/3's I bought earlier in the year were pretty good in the rain, were very warm when not raining but where bought more for winter riding than summer…

Agree with tinsy, that mud gaurds are a must as well.