The days are longest in summer and shortest in winter. The shortest day is June 21st and the longest is December 21st in Sydney Australia. See: http://www.archaeoastronomy.com/ for your area.
For daytime VFR flights you may not take off prior to first light and you must be landed 10 min prior to last light.
It is your responsibility to plan and allow for delays and still land at least 10 min prior to last light. The longer the distance, and the closer to end of day, the more room for error you need to allow.
Even for extremely skilled pilots landing in the dark on fully lit runways is very difficult. Don’t risk it ever.