Like the Mercury, Booker and Turner, it’s not for 2020 it’s for a time period that straddles years.
This time of year when students go (back) to uni used to be a really key time for people to buy music and discover a new favourite band before the big Christmas campaigns started, so a lot of awards tended to be about now.
Also I’d imagine running any album of the year list in December wouldn’t get much coverage or have much impact nowadays.