I don't think it's a "must have" feature cause it can be "easily" done by some web coding based on logs but it would be nice to have a function included in Cumulus (and webtags ) to show the current weather conditions and sky condition. If people have a solar data they could easily "detect" from that the sky condition : some clouds, cloudy, overcast etc.. and for those who don't have it they would use the nearest METAR updates. When some event occurs which the station can detect like light rain, showers, rain, heavy rain, thunderstorm those values override the METAR.
This is completely a web related thing, if a visitor sees the current conditions in your web page I think it would a lot more instructive to know what exactly is going on in weather terms, not only temp and hum!