There are 4 season cycles, Winter, Autumn, Summer, and Spring. These are signified by the color of the trees as that is the only way to tell other than the weather too. They also signify the specific Natural Disasters. Each season lasts about 15 minutes, although they can differ.
Spring - Trees turn pink and flooding may occur. The level of the flood differs. After a flood, fog appears, limiting the player's sight which is seen as annoying. During spring, like summer, herbivores and omnivores may eat leaves from the trees. Raining may occur. Ferns appear in large numbers across the map.
Summer - Trees turn green and droughts may occur, in which rivers and lakes dry up almost completely. During summer, herbivores and omnivores may eat leaves from the trees by left clicking, given that they can reach. Ferns are common.
Autumn - Trees turn yellow/orange and are inedible. Flooding occurs, level and length of the flood differ. After a flood, fog appears, limiting the player's sight. Ferns start to disappear.
Winter - Trees turn white and are inedible, and the water has a chance of freezing. When frozen, the player may left click on the ice multiple times and a light blue blob/circle will appear, allowing the player to drink water. Ferns are almost inaccessible.