December 20[edit]

1947: The Hydrometeorological Institute of Montenegro began operations.

2006: The first of two blizzards within a 9-day period crippled the Front Range Urban Corridor of Colorado with up to 32 inches (81 cm) of snow.

2010: Tropical Storm Omeka formed near the International Date Line, and moved east into the Northeastern Pacific Ocean. This is the latest on record that a tropical storm occurred in this area.