‘Cold Moon’ lunar event at peak for Boxing Day

The night sky is expected to be quite a sight on Boxing Day.

A phenomenon called the “Cold Moon” or “Long Night Moon,” which happens every 19 years or so, is the first full moon since the Dec. 21 winter solstice.

The moon is expected to rise near sunset on Dec. 26 and 27, with the peak happening on the 26th. People were treated to a “Christmas Moon,” a full moon on Christmas Day, 2023.

NASA says the full moon takes a high trajectory across the sky because it is opposite to the low sun, so the moon will be above the horizon longer than at other times of the year.

Here in Calgary, the online moon rise calculator says it will rise at around 3:44 p.m. MST and be most illuminated at 5:33 p.m., and it will set shortly after 9 a.m. Wednesday.

Its name derives from the fact December is based on the frigid conditions of this time of year, and the Old Farmers’ Almanac says the name comes from Mohawk traditions.

NASA says it’s because December is a really cold month, “although our coldest average temperatures are in January.”

“The Long Night Moon gets its name because the full moon in December occurs near the solstice, which has the longest night of the year,” it said.

In addition, the almanac says Europeans call the December full moon the Moon before Yule. Yule is an old northern European winter festival that is now associated with Christmas.

It last happened in 2015 and is expected to return again on Christmas in 2034.