Watch it live A rare super blue moon will shine in the sky as August wraps up. The month already featured a supermoon as it began, but the second full supermoon of the month — which will appear on Aug. 30 — will also be a blue moon. A blue moon is not actually blue in color; the term signifies a second full moon within a single month. August's first full moon rose on Aug. 1 and was the second of four consecutive supermoons. On average, supermoons are about 16% brighter than an average moon. They also appear bigger than the average full moon. According to NASA, it's similar to the size difference between a quarter and a nickel. The phenomenon occurs when the moon's orbit is closest to Earth at the same time the moon is full. The Aug. 30 supermoon will appear to be even closer than the full moon at the beginning of the month.