Study the Stars
Priests looked at the stars to determine the best times  for tilling the fields and planting and harvesting crops. This is how they created the two seasons, winter and summer. They created this calender based on the moon phases. This calender had twelve months with thirty days.

This has helped people in the future to decide when to farm  allowing them to settle in permanent homes. We still use the 12 month calender. The two seasons help us be prepared. For example we can get ready for the winter.