The moon will not actually shine in blue, but it is given this name because it is the second full moon to appear in the same month, with the first occurring on October 1, and the second on the 31st of the same month.
And this cosmic display occurs seven times every 19 years, which means that the world will not see the next show until October 31, 2039.
What makes this event even rarer is that it will appear worldwide for the first time since World War II, since 1944.
And heaven will bestow this rare sight with a second full moon in October on Halloween night.
People in North and South America will get a glimpse of the blue moon, along with those in India, Europe and Asia.
The full moon can turn blue, but this signature is extremely rare, and EarthSky explains that sky conditions must contain large particles of dust or smoke to reflect a blue hue.
Altogether, there will be 13 full moons in 2020, which is another rare occurrence because most years only see 12 full moon.
Source: Daily Mail