A blood moon eclipse, which is a total lunar eclipse where the Moon appears reddish, typically occurs about 2 to 4 times per year. However, total lunar eclipses, which produce the blood moon effect, happen less frequently—about every 2 to 3 years for a total eclipse visible from any single location. Additionally, rare sequences of four total lunar eclipses over about two years, called lunar tetrads, occur only occasionally every few decades. Lunar eclipses happen approximately 2 to 5 times a year in general, but not every eclipse produces the blood moon coloration, which is due to the Earth’s atmosphere filtering sunlight during totality.