The blue moon itself, i.e. the second full moon in the same calendar month, is a relatively rare phenomenon, because it occurs on average once every 2.5 years - it is enough to mention that in English there is even a saying "once in a blue moon", which just means something very rare. And since everything has to be unbelievable this year, the blue full moon falls on Halloween, and this coincidence happens on average once every 19 years. Little? Here you are, this year, for the first time since World War II, this phenomenon will be visible from all regions of our planet, not just some of them.
"When I was teaching, my high school students believed that there was a full moon every Halloween," explains Jeffrey Hunt, astronomy teacher and former planetarium director. And although this is the image that popular culture promotes, for example through films, it is a bit different. For example, the last Full Moon to fall on Halloween and visible to the entire world was in 1944! Admittedly, a bit later, in 1955, we had the Halloween Full Moon visible to much of the world, but without Western North America and the Western Pacific.
This time it will be different and tech guides best will also enjoy it, so it's worth taking a break from watching horror movies and eating candy to see this fullness with your own eyes. It is worth remembering, however, that although the phenomenon is called a blue full moon, unlike other similar phenomena, e.g. the bloody moon, it does not change the color of the moon to blue - interestingly, due to appropriate weather conditions you can sometimes notice a blue glow, but it is better to it doesn't count. And remember, if you miss the Halloween Full Moon this year, the next one isn't until 2039!