My example suggestion from night to day
Day = 3-5 post, the following 3-5 post after that in the topic = night. A minimum of 10 post will have meant a full day has gone by if RP'd correctly. (I.E the RP'er states that the sunrises,its the afternoon, its twilight, sunsetting, and its midnight, or just states the time like 3.00am, any other characters in the same topic must follow the last time-frame)
50 post will mean an entire week in your storyline has gone by ( battles depending on ifs apart of your story or not will be either included or not counted for of towards your bio and player timeline -which should be kept inside of your bio posted day by day of events that took place... In short save your progress and keep up with what your character has gone through)
150 post ((Once again only post directed towards your storyline will count, general, suggesstion post will be unaccounted for towards your timeline))
1800 post will be equivalent to an entire year.
Not all RP areas will be affected by seasonal changes maybe a little construction; but not a single sign of leaves coloring will change in an area where it always snows. Just be logical with your enviroment.