Each season lasts a week (real time) in Age of Farming. They can bring harsh temperatures that increase the energy consumption of poorly equipped workers. Each Age can bring different seasonal effects.
Spring: As winter recedes, players must plan their actions for the following year. Production is no longer burdened and the focus must shift on growth.
Summer: Wildlife reaches peak growth in the summer heat. This is a very productive season, but starting with the Neolithic, as the Ice Age ends and the planet warms up, working in the summer will also require proper clothing.
Autumn: Autumn is a moderately productive season and it's the final chance to begin making the necessary winter preparations.
Winter: The cold keeps people close to the fire. Working in the winter without warm clothing results in very high energy consumption.