My hair is wavy and has always been prone to frizz, especially in damp conditions (which, let's face it, is 90% of the time in the UK).
About a year ago, my hairdresser started using a product called "Sweet Hair" (I hope I can say this - I have absolutely no connection with the company). It is a Brazilian product and has to be applied in the salon and hair straightened afterwards. It isn't cheap, but it lasts for 3 months and I can honestly say that it has transformed my hair - I can just give it a quick blow dry when I wash it (2 or 3 times a week) and no more frizz!!