I had also heard & read that this could be an issue due to the curvature ar the base of the visor. So I got a Raleri anti fog insert (specific to Arai). I've had them for a while on another helmet too ...

It has deployed truck-mounted fog mist cannon units across all 24 zones, besides over 100 tankers dedicated to street cleaning activities. The fog mist cannon units are operated in two shifts in ...