Gill nothing works bud ,if its so called breathable fabric it will leak at some point ,,and if it non permeable fabric ,ie oil skins and the like you sweat a lot if you are grafting ,,I have tried them all ,the best thing to do if your working in the rain all day is take a complete change with you, everything right down to your kegs .. and change at lunch time it makes working in the rain tolerable
Or you can do what we did on a big roofing job were it rained every day for 10 weeks,, was big breakfast in the morning and work until you are drenched no breaks for tea and then go home,, we were finishing at about two to three o'clock but still got the job done on time ,keep something dry to change into for the journey home