The blue moon also will be a super moon, which occurs when it is at or near its closest point to the earth, or perigee. A super moon is about 14 percent brighter than usual, the National Aeronautics and Space Administration said.
Wednesday's moon will be the second closest of 2018 after the one on Jan. 1.
The lunar eclipse, which takes place when the moon passes in the earth's shadow, will last almost 3-1/2 hours. It will start at 6:48 a.m. EST (1148 GMT) and peak at 8:29 a.m. EST (1329 GMT), NASA said.
The total eclipse will be visible from the western United States and Canada across the Pacific Ocean to most of Australia and China, as well as northern polar regions. The eclipse will give the moon a reddish color known as a blood moon.
"I'm calling it the purple eclipse because it combines the blue moon and a red eclipse," Rich Talcott, a senior editor at Astronomy magazine, said by telephone.