If you don't already believe in superstition, this moon will show you the writing on the wall.

From coronavirus to zombie cicadas, 2020 has felt like one long horror movie. However, the shocks and spooks aren’t over yet. This Halloween, you’ll be in for another treat as the moon transforms and shows us what the saying “once in a blue moon” really means.

On Saturday, October 31, the night sky will showcase a rare full blue moon. This superstitious phenomenon only occurs when there are two full moons within one month or when it’s the third of four full moons within a season.

The blue moon that will occur on Halloween is a result of two full moons within a single month. Therefore, we’ll see a full moon on October 1 and the full blue moon on the 31st. According to NASA, a blue moon only occurs once every two and a half to three years and according to the Old Farmer’s Almanac, a full moon only falls on Halloween once every 19 years.

The blue moon isn't named after its color, but rather when it occurs. According to NASA, most blue moons appear as pearly gray to the human eye, but sometimes the moon does appear blue in color. This depends on the atmospheric conditions around the time of the full moon. For example, in 1883, a blue moon appeared blue after the volcano Krakatoa erupted and dust rose into the air.

While this year's Halloween moon is unlikely to be blue, it wouldn't be too surprising if we do spot some blue hues (with how this year is going).

If you miss out on the blue moon this Halloween, the next time you’ll be able to see one is on August 22, 2021, and the next time you’ll be able to catch a full blue moon on Halloween will be in 2039.

So, will you be on the lookout for the blue Halloween moon? Let us know in the comments!