A MYSTERIOUS halo could be seen around the moon in skies across  Gwent last night. 

From around 8.30pm, a strange thin circle was seen around the moon in skies throughout Gwent. 

According to the Met Office, this natural phenomena is called a 'moon halo' and can be a sign of forthcoming rainfall or storms, particularly in the summer months.

The Met Office adds: "They are caused by ice crystals that are formed in high clouds. These ice crystals then refract the light from the Moon or Sun. As the ice crystals travel lower, precipitation becomes more likely."

Although haloes have appeared throughout the UK before, for some people in Gwent, this was their first time experiencing one, and some have shared their fascinations on social media, including sharing their own pictures. 

There have been images of the 'moon halo' captured in Blackwood, Undy, Gilwern and Cwmbran by eager snappers. 

South Wales Argus: Moon halo captured in CwmbranMoon halo captured in Cwmbran (Image: Nathan Edwards)

South Wales Argus: The halo was spotted from a back garden in BlackwoodThe halo was spotted from a back garden in Blackwood (Image: Julian Potter)

South Wales Argus: This beautiful shot captured in UndyThis beautiful shot captured in Undy (Image: Larry Wilkie)

According to the Met Office, some haloes can have a faint colouration if the light rays reflected strike the moonlight from a particular angle, causing some light to be refracted. 

The most frequent type of haloes are named 22 degree haloes as they commonly have a 22 degree angle of refraction through six-sided ice crystals, however, since crystals can have a different structure or be at a different angle to the sun, they can vary, including small ones at seven degrees and larger ones at 46 degrees, or even only a part halo, which appears to look like an arc. 

The Met Office adds: "In the past haloes and other such atmospheric phenomena were used as an empirical form of weather forecasting before the development of meteorology. There is some degree of truth in this. 

"The high cirrus cloud which contains the ice crystals required for haloes to form often signifies an approaching frontal system; however in many cases the front will be inactive or simply change course from the area - producing no rain."