I upgraded my newton to the Newton 6 (it is a body upgrade for a Newton 5 - if you have that). Otherwise the best technical solution for older Newtons is the 'remote wind sensor' which is a hose with collection horn and a back end plug to fit the wind port.
This will block rain from being able to clog the wind port. I had one on my old Newton, worked in the rain.
The Newton 6 body upgrade has also made a non-issue for me. The older Newtons did have some weakness in heavy rain.
There is a repair ride file for blocked wind sensor feature in Isaac you can use too.
made it diferent. newton is a great tool to start using with watts, i love it. but i got so depedent in the watts that when it did not work, the race whent very wrong...