The standard Blue Moon is 5.4%. There's a 3.2% variant, but it's only sold in a handful of U.S. states (like Utah and Oklahoma) that have a 3.2% cutoff for beers sold at convenience and grocery stores.

3.2% by weight or volume? Most of the 3.2% beers are measured by weight because it is related to some state law that specifies alcohol by weight. This translates to about 4% by volume.