Because of the shorter days in Winter the work day went until 5:00.  Since the 16th Century the work day would end at 6:00 after the spring equinox.  Sechselauten means the 6 o'clock ringing of the bells, this also determines the beginning of Spring.
 

The long standing tradition is what’s known as the burning of Böögg (which could mean Bogey man).   The Böögg head is filled with fireworks and then it is burned at six o'clock, depending on how long it takes to burn and the head to explode determines how long or short the winter or summer will be.  The longer it takes to burn the longer the winter will be.