Why sand is drier than clay?

rn

 

When people think of sand, they think of hot, dry beaches, sand castles glistening in the sun, and tiny rocks stuck everywhere. Clay, however, is thought of as dense, wet mud. Both sand and clay can be dry or wet, but sand is notoriously drier than clay. This phenomenon has to do with the way the sand and clay particles fit together.

or

its porous

 All things being equal (which, of course, they never are), sandy soil will feel drier than clay soil because sand provides better drainage, mainly because it far more porous than clay. Clay is dense, less porous than sand, and acts somewhat like a sponge.

actually 
sand is less porous then clay but other then that the above answer is fine. clay has a better ability to retain water like a sponge.