I'm not sure the anticorrleation has ever been proved. While it seems logical, the cloudy / stormy weather that sometime we experience in UK is too harsh for wind farms
If you look at graphs of the wind and solar production in winter vs summer, the correlation is obvious. On a day-to-day basis, much less so, but on average low wind does tend to come along with higher sun.
This only happens in the designed operating window ( too light you get nothing, too strong you need to shut down ).
So one question is what window have your tuned your farm for?
Air density matters as well - the denser the more power - ie the colder the more power.....