How is photosynthesis effected by winter?

Typically, in winter there is less sunlight. The light that does reach the plants is weaker as the Earth is tilted further away from the Sun in winter. Plants are unabe to photosynthesize without sunlight, it is the power behind the entire process. Also, plants are unable to photosynthesize without water. In the depths of winter, much of this may be locked up as ice and therefore unaccessible to most plants.