A penumbral lunar eclipse occurred at the Moon’s ascending node of orbit on Tuesday, May 25, 1937, with an umbral magnitude of −0.3033. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A penumbral lunar eclipse occurs when part or all of the Moon's near side passes into the Earth's penumbra. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. Occurring only about 18 hours after apogee, the Moon's apparent diameter was smaller.