The full moon in May is traditionally known as the Flower Moon, because it appears whn the flowers are blossoming.
The moon follows an elliptical, rather than circular, orbit around the Earth.
When a full moon is at its closest point to earth (the perigee), it is ~17,000 miles (28,500km) closer to earth than average.
It appears ~7% bigger and brighter in the sky and is therefore known as a supermoon.
This happens 3-4 times per year and this month's is the last of three-in-a-row that began in March.