Flying through clouds currently does nothing to the airplane.
When a real airplane flies through clouds, below a certain speed, the bow wave cannot shove water droplets out of the way, so they hit the windscreen like rain.
Since there already is a variable “AMBIENT IN CLOUD” and “ENV CLOUD DENSITY”, as well as Airspeed-variables, I propose the following to achieve the above described effect:
Simulator-Side solution: Set “AMBIENT PRECIP RATE” to a value determined by “ENV CLOUD DENSITY” and “AIRSPEED TRUE”, with the “AMBIENT PRECIP STATE” set to “Rain”.
Moddable solution: Make the variable that is controlled by the slider “Rain Rate Overwrite” in dev-mode, as well as the one that controls the wind on the windscreen rain effect, available to WASM modules and make it writeable. That way, WASM based mods could be used to apply this effect to any aircraft, and aircraft developers can implement their own custom solution to take into account the effect of the nose shape on the amount of rain drops hitting the windscreen.