@rbush Hi, it is not clear if you are talking about current conditions or forecast.
Windy capabilities:

Forecast: a few weather models which you can compare Current conditions: meteostations, metars, radar images

Which of these products do you find inaccurate?

About clouds forecasting: It is tricky in many cases. Fog or small-scale convective clouds are hard to predict even for the current day. It happens often that fog is not caught by clouds layer at all.

About metars: They code real measurement and I do not expect that they are wrong. Only thing which comes to my mind is that they can be outdated.