A blue moon happens once every two to three years and is where there are 2 full moons in a calendar month rather than one, or four full moons in a season, or 13 full moons in a year rather than 12. Hence the term once in a blue moon which refers to something rare. The term for this extra full moon has nothing to do with the moon actually appearing blue, though on rare occasions, dust or smoke particles may give the moon a blueish hue. But this year is rarer in that we'll have two bluemoons, one on the 31st January and one 31st March.
The last time there was a full moon was on New Year’s Day and we will have another full moon on Wednesday 31st of this month. The bluemoon on Wednesday will also be a supermoon, when the moon is at or near its closest point to the earth, with Wednesday’s full moon the second closest to the earth this year after New Year’s Day and some 14% brighter than usual.
Some parts of the world will be treated to a super blue blood moon, which is the second full super moon in a month and blood moon or lunar eclipse. The last time all these occurred together was in 1866. The lunar eclipse, when the moon passes through the earth’s shadow, will last up to three and a half hours, with a total lunar eclipse visible across western hemisphere including western North America across the Pacific Ocean, including Haiwai, across much of Australia and China, as well as northern polar regions. Those living in North America will be able to see the eclipse before sunrise on Wednesday, those in the west coast, Alaska and Haiwai can witness, weather permitting, totality of the eclipse from start to finish. For those in the Middle East, Asia, eastern Russia, Australia and New Zealand, the event will be visible during moonrise on the morning of 31 January. The eclipse will give the moon a reddish colour giving it the name blood moon.
For the UK it will be a super blue moon only, the moon will be fullest at 13:26 on Wednesday afternoon, best visible on Wednesday evening. Weather conditions are looking good for parts of the UK on Wednesday evening too. Wednesday morning will see a cold front sweep southeast, followed by a cool northwesterly flow, bringing some showers to western coasts and areas of cloud parts elsewhere across the UK Wednesday evening, but there should be some breaks to see the moon, particularly areas sheltered from the northwesterly wind.
Also we will be able to see the space station in the sky early evening, cloud permitting, look out for a fast-moving bright light!
So, we’ll see a bluemoon on Wednesday then in February we’ll have a blackmoon, i.e. no full moon in the whole calender moon. March will again have two full moons, one on the 2nd then a bluemoon on the 31st. Two blue moons in a year is pretty rare event!
We miss out on the Lunar Eclipse this time, but on the 27/28th July the UK will be able to witness a total lunar eclipse, more on this here