White-tailed deer start growing antlers in March or April as the days start to lengthen. July marks the peak of their antler growth season, hence the name Buck Moon. Thunderstorms are also common in July, which is why it's also called the Thunder Moon.

The Old Farmer's Almanac, which began publishing full moon names in the 1930s, says some Native American tribes called July's full moon the "buck moon" because it occurs in early summer, when male deer (bucks) typically begin growing new antlers covered in velvety fur.