Plant Growth Slows During Cooler Weather

• When the temperature gets cooler, plant growth slows down. If cool temperatures occur in the early part of the growing season, this can delay the emergence of leaves. Cool temperatures accompanied by cloud cover can slow down photosynthesis in plants. Colder temperatures and shorter days tell deciduous plants it is time to stop growing and plant leaves change color and fall off the plants. In northern and southern climates, autumn is due to the change in temperature and day length.
  
  

Animals Become Dormant or Migrate

• When the temperature begins to drop in the fall, animals adapt to the changing temperature. In some animals, like Canada geese, the shorter days and the cooler temperature cue the animal's body to migrate. Other animals begin to grow a winter coat in response to the colder days and they prepare their winter den sites. Invertebrates, like spiders and slugs, lay eggs under logs to ensure that their babies make it through the winter.
  
  

The Water Cycle Changes When It Is Colder

• As the temperature cools, the movement of water through the environment changes. Less water evaporates and more water sinks into the ground or flows over the ground. When it rains, the ground becomes saturated and water flows into rivers and lakes. The rivers and lakes become full and may flood if it rains a lot and water does not evaporate. In areas with migratory fish, the combination of seasonal timing and high water levels tells the fish it is time to migrate up the river again.
  
  

Falling Leaves Form Soil

• When the temperature gets cooler and plants drop their leaves, soil forms. Cool, wet weather tells mushrooms it is time to fruit, and these mushrooms act as decomposers of the plant material that has fallen to the forest floor. When it is cool but not cold, soil invertebrates and microorganisms also decompose leaves, turning them into soil that will sustain plant and animal life in the warmer times of the year.