You have to check the Farmers Almanac for your area to get an idea of when flowering will begin.

The sun will eventually start going down at about 7pm, and rising at 7am, and that's when flowering begins. I'm on the West coast of Canada and flowering ends in March for very early harvests, but typically flowering begins around the beginning of September, or ending August, and harvest won't be until mid October.

Back in Alberta it was very hard to do either harvests. March it is freezing, hell, until mid May it still freezes overnight, and good luck getting a plant to stay free from frost until mid October. The first freeze starts around Sept. 20th.

Stupid Alberta. BC kicks so much ass.