What do the words spring and autumn denote?

Spring is one of the four seasons in the Temperate Zone. It is March, April, and May. Nature awakens and flowers bloom.

Autumn (in the USA Fall) is one of the four seasons in the Temperate Zone. It is September, October, and November. Summer is over, leaves fall, nature is bownish yellow. It often rains. Our mood is usually worse than in spring.