Now with live weather having convection I often find good gliding condition near clouds with rain. Thanks to contact with GotFriends team I was informed that sadly flying through the rain doesn’t have any negative effect on glider polar as simply MSFS doesn’t provide any sim variable that would allow detecting flying in the rain (there is a variable that informs about flying in the cloud, so it seems like an oversight) - I confirmed it expermientally by flying throuh many rains had good lift there and not seeing increased sink leaving the rain. I was assured by GotFriends that as soon as they get such variable they will be able to implement proper polar degradation.
In RL it is very important to know how given glider wing profile behaves in the rain as some very good gliders can have polar drastically worsened by droplets making micro turbulence (it is easier to stall also).
It is also important for other factors - RL Discus 2c FES manual says:
It is allowed to fly through light rain with the motor running. However, use lower RPM settings, suitable for horizontal flight, to avoid damaging the propeller blades. Stop the motor if the rain becomes stronger.
I wonder if the team that officially implementing gliders is aware and will request & properly simulate flying gliders in rain conditions, but maybe there is no need to wait - is there a way for plane/glider devs to ask MS/Asobo for such variable (it would be good to know how heavy is the rain, so not just a boolean)?