Spectacular Moon (Lunar) Halo: Weather Folklore

              Last Monday night, January 13, 2014, a spectacular halo around the moon left people enthralled and reaching for their cameras to share on social media. According to scientists, the unusual phenomenon, which happens during cold months, is caused by sunlight refracted in millions of randomly oriented ice crystals in the atmosphere. Though considered by many as a magically significant event, there’s a scientific explanation regarding this phenomenon for us to understand more about how it happens.

The Ring Around The Moon

               

                The ring around the Moon is caused by the refraction of Moonlight (which of course is reflected sunlight) from ice crystals in the upper atmosphere. The shape of the ice crystals results in a focusing of the light into a ring. Since the ice crystals typically have the same shape, namely a hexagonal shape, the Moon ring is almost always the same size.

               

                 Less typical are the halos that may be produced by different angles in the crystals. They can create halos with an angle of 46 degrees. (http://home.hiwaay.net/~krcool/Astro/moon/moonring/)

Moon Ring Weather Folklore 

             

                 I was alarmed when I read some of the comments of the netizens stating that the particular phenomenon connotes negative news regarding the weather for the coming days. The optical phenomenon seems idealistic for some and is definitely awesome to look at. However, from a folkloric standpoint, they claim that a halo around the moon warns of a coming bad weather or storm, or other foul atmospheric conditions are on the way. Some of them said that in many cases this may be true. 

                 So I wonder, how can rings around the moon predict a bad weather? 

                 

                After reading the "Moon Light Effects" (http://home.hiwaay.net/~krcool/Astro/moon/moonring/), I found out the possible reason behind the rumor. The ice crystals that cover the halo signify high altitude, thin cirrus clouds that normally precede a warm front by one or two days. Typically, a warm front will be associated with a low pressure system which is commonly referred to as a storm. 

                A few days after that moon halo, Agaton came-the first tropical storm that's beating the country this year over large areas of Visayas and Mindanao. Well,  it is indeed true!