solar sensor

I have read in various threads that some combination of one-wire humidity,solar and temperature sensor is being used but not just a solar sensor.

I would like to add a sensor to provide sky conditions and wonder if just the solar sensor will be adequate?

In my opinion yes. I did run my Hobby-Boards like that for a while but then I wanted to know what the temp was like inside the enclosure and added a temp sensor to the board.