Pokémon Black and White/Seasons

In addition to the day and night cycle first introduced in the Gold and Silver games, Black and White introduces a seasonal cycle, with the seasons advancing every month, cycling every four, rather than being linked to the actual calendar. Outside areas appear differently depending on the season, such as changing of leaves in autumn or snow on the ground in winter. Certain areas are only accessible during certain seasons, and different Pokémon can be found in the wild in winter where others are encountered in the other seasons. In addition to these features, the Pokémon Deerling and Sawsbuck were designed to change their physical appearance along with the seasons of the game.