Stir water and sugar together in a saucepan until sugar dissolves. Add lemon, cloves, and cinnamon stick; bring mixture to a boil and cook until flavors combine, about 10 minutes. Strain and return water mixture to the saucepan; discard lemon, cloves, and cinnamon stick.
Stir claret wine into water mixture; heat until hot but not boiling, 5 to 10 minutes. Serve flecked with nutmeg.