What brake pads do you use? If any

The perfect solution is to ride more slowly, squeegee your rims regularly, and modulate braking appropriately.

+1 to koolstops (dual compound).

I find, if you have a good angle on the pads, you can clean the rims with the first part of the pad, and then engage the rest to stop/slow. The fibrax pads seem not to grip very well regardless though.

I shall investigate Koolstop.