Originally Posted by RWood
It's likely that the 300.4 hrs for Sydney Aero recorded one August was about 89% of the possible, given the technology used, so not far off. On the same basis there looks like an 85% for one September, not a winter month though.
Oops, forgot about this one!
. Now you mention it, that was in August 1991, 24 days exceeded 10 hours and only one day had no sun.
The September one was in 1980 (302) with 20 days exceeding 10 hrs and the lowest total was just 5.2.