Trying to work out which day of the year should sun be prevented from entering a window

What I have done this afternoon is analyse the weather file for Melbourne, Essendon Fields and see where the cooling degree days on a monthly per hour basis was then deconstructed per day of year to find when artificial cooling was no longer necessary in Melbourne. From what I can interpret, the weather data file has told me that on the 93rd day of the year (add one because the list starts at zero)(April 3rd) is the first day without any without any cooling hours required and 228th day of the year (August 16th) is the first day with cooling hours required. I am trying to design the length of the hoods over the windows and the sill height to optimise best time for sun penetration. I have not found a simple Ladybug tutorial to help with this situation. Any suggestions?