"Dr Smith" writes:

I know Flightsim doesn't model it however does anyone remember which of the
past Flight sim products did model the effects of flying through rain...

Microsoft Flight Simulator definitely models flying through rain, and it has
been that way for years. Set the weather conditions up for rain and you'll
see and hear it inside the cockpit and see it in other views as well. It also
moves realistically as your airspace changes.

However, wet runways are not modeled in FS2004, and I don't think they are
modeled in FSX, either (?), at least with respect to aircraft performance.