Why do snowflakes always have six sides? 

They accurately reflect the molecular structure in the form of crystal water in the solid state

. In this state, each molecule is surrounded by four other at the point at which hydrogen is fixed, and oxygen atoms are arranged in layers, forming a hexagon.

 After the first crystal is formed, other water molecules are added at the corners of the initial molecule, forming the branches of the flake.

 "Even when having six sides, crystals appear in various forms.

 Familial is in most branches, but there are others such as plates, needles or prisms depending on the temperature of crystal formation in the cloud"