Cheap rain gear that works and packs up tight for touring. I have never tried this stuff but read many great reports on it being 100% waterproof.

http://www.froggtoggs.com/?outerwear/travel

http://www.ebay.com.au/itm/FROGG-TOGGS-PRO-ACTION-PA-102-RAIN-GEAR-SUIT-GOLF-BOATING-FISHING-HIKING-GAMES-/230746862384?pt=US_Men_s_Athletic_Apparel&var=&hash=item7b692365a1