I am a supporter from China.I love Windy.
I think that visibility prediction inaccurate is a need to solve the problem.
And Hope the Windy to be better and better.
Visibility is a very difficult variable to predict.
According to ECMWF (https://software.ecmwf.int/wiki/pages/viewpage.action?spaceKey=DSKB&title=Visibility+Parameter ):
"The visibility diagnostic is an experimental product introduced in 2016
and the quality of this product is undergoing continued evaluation .......
It should be used with caution; expectations regarding the quality of this product
should remain low."
.... "The current technique for visibility forecasting has several limitations;.....
Model horizontal resolution is relatively low, and the lowest level in the vertical is 10m so capturing the detailed extent and composition is difficult, especially in rugged areas. ..... Visibility is still a relatively new product and undergoing continuing assessment."