Stir together the water, lemon juice and agave nectar in a medium saucepan and set over medium heat. Cook, stirring, until the agave nectar dissolves.

Add the whiskey, cinnamon stick and cranberries. Turn down the heat slightly and simmer until the cranberries have popped, about 30 minutes. Taste and stir in more agave nectar, if desired.

Divide into 4 glasses or mugs, and serve with lemon wedges.