This cloud map can show the 9am or 3pm average annual or average
season or average monthly cloud distribution across Australia based
on 15 years of records from 1976 to 2005.
Use the 9am and 3pm checkbox and the "Period" pulldown to change the dataset.
This is only cloud and it doesn't take seeing into account. I've spent months in the Kimberley where it was clear every night but the seeing was rubbish due to the heat haze - not to mention smoke at the end of the dry season. Personally I reckon 1-2 nights per week of 8-9/10 seeing is better than 6 nights per week of 5-6/10 seeing. And both are better than what most of us endure!!