Seasons
In Fields of Mistria, there are four Seasons: 
Spring, 
Summer, 
Fall, and 
Winter. Each season lasts 28 days (4 weeks) and together these 4 Seasons make up a single in-game year. The game begins on Year 1, Spring 1. Upon the end of each in-game year, the seasonal cycle will restart, beginning again on the next year, Spring 1.
There are several aspects of the game that are affected by the season.
Each season has its own respective Festivals. Festivals are special events where Villagers will gather to engage in special activities. This includes holiday-specific games & prizes, items for purchase and special dialogue.
The season determines the Crops that can be grown, Forageables that can be found, as well as the Bugs and Fish that can be caught; among other things. At start of a new season (end of day 28) any Crops planted will wither and die, unless they are also able to grow in that season. Fully grown Fruit Trees will stop bearing fruit when not in season.
Some aspects of the game are not affected by seasonal changes, and some seasonal changes are more aesthetic and visual based than mechanics based. (For example, the changing colors of outdoor scenery.)