Fair weather cumulus clouds are often seen during sunny, breezy
days. These clouds have piled up, puffy tops (the word cumulus
literally means "accumulated"), and often appear to have flat bases.
To learn more about clouds and cloud identification, visit the University
of Illinois at Urbana-Champaign Weather World 2010 Clouds
and Precipitation Online Guide or the Plymouth State College
Meteorology Program Cloud
Boutique.