For the first time in 38 years, there will be a full moon on Christmas.  Even though a full moon occurs every 29.53 days, it has been a long time since the full moon and the date of December 25 lined up.  You can read more about it at IFLT Science and at EarthSky using the links below.

https://www.iflscience.com/

https://earthsky.org/

Source: JustLiza, Commons Wikimedia
Source: JustLiza, Commons Wikimedia