The solstice will be in a couple days here (Dec 21) and as the days shorten flowering will commence. I've grown for years outdoors (N Hemisphere) and I usually start seeing flowers by Sept 1, when there is 13 hrs between sunrise and sunset, and close to 15 hours of some type of light including sunrise/sunset and twilight conditions. Sept 1 would be more like March 1 in the S hemisphere.
If you're growing in sunlight you are at the mercy of your day length and genetics, unless you want to artificially shade the plant.