Career
Winkmann started his refereeing career in 2001, and in 2004 he was promoted to the 2. Bundeliga. In 2011 he was promoted to the elite group of referees who referee the Fußball-Bundesliga. His first Bundesliga match was on 16 August 2008 when he refereed Energie Cottbus and TSG 1899 Hoffenheim
Personal Guido lives in Kerken and is a police officer