It's good to know the seasons. I split it into four seasons, 3 short one long. Short season is from nov-march, July-oct, and oct-dec. the long season is from May to sept/oct depending on what kind of strains. Also my seasons overlap so I don't run out
Also know when solstice is. the amount of sunlight hours will increase from December 21st (shortest day of the year) and decrease after June 21st (longest day of the year).
Also good to know when equinox is. (When sunlight is 12hrs and night is 12 hrs) this occurs around the 20th of march and the 23rd of September. This is how u can determine if days at getting shorter or longer for flowering and veg.
The moon also affects sprouting and harvesting. I find that planting is better on a new moon and harvest on a full moon (hence harvest moon). Think this has to do with gravitational forces from the moon much like tides.