Halloween will bring the second full moon of the month. The second full moon in a month is called a Blue Moon. But that’s not all that will fulfill your astronomical wonderment on All Hallows Eve.
A red Mars will be visible very close to the full moon. Mars is just past its closest approach to Earth in two years so it will be a welcome sight you’ll be able to observe without a telescope. According to the website Earthsky: “People will also call this full moon a micro-moon because it’s the most distant (and smallest) full moon in 2020 (252,380 miles or 406,166 km).”
You’ll have to wait a while to see the next monthly Blue Moon (second full moon in one calendar month) it won’t come until August 31, 2023.