How do seeds know when it's time to grow? People have calendars that tell them when to plant their seeds, but many processes in the wild must find their own ways to conform to the rhythms that underlie life in the different biomes.

     One mechanism that plants and some insects use is recording and acting on degree days.

     How do we calculate degree days?

Record the high and low temperature for each day.

Add the two temperatures together and take the average.

 

Example:

It is winter in the forest.

Highest temperature	90
Lowest temperature	60
Highest minus Lowest	150/2=75-32=43
Number of Degree Hours