The Uniform of the Day, when referred to in a military sense, is the designated uniform all military personnel are required to wear on that particular day. It is often designated by the senior officer on the base. Normally the uniform is determined by the seasons (e.g. winter blues or summer whites for Navy) however, special occasions (e.g. visiting dignitaries) or weather changes may also dictate changes to the uniform of the day. The uniform of the day instruction is broadcast over the 1MC at reveille on board U.S. Navy ships.