Unreasonably cold temperatures have been just one aspect of an unusually harsh January in Toronto. But while these weather extremes have brought chaos to city streets and put vulnerable populations in danger due to the cold, they've come with a pretty spectacular silver lining for skywatchers.

It may not be as awe-inspiring as the aurora borealis — rarely seen around these parts — but another uncommon phenomenon has been lighting up skies around Toronto on some of the most frigid nights experienced this January.

Known as light pillars, these vertical beams of light are an atmospheric optical phenomenon caused by the reflection of light through ice crystals suspended in the sub-zero air.

In the right cold and calm conditions, these tiny hexagonal crystals act as clusters of millions of micro-mirrors that reflect light upwards to form stunning streaks stretching skyward.

The light source can come from the sun when low on the horizon in cases known as sun or solar pillars, but when these beams occur after dark, the optical effect is either fuelled by moonlight or from sources closer to the ground like streetlights or buildings.

The latter is what is being witnessed over Toronto and surrounding area skies this winter, evidenced in photos that show moonless skies and vertical streaks rising from visible light sources below.

It's hard to do justice with still photos and even video, but a roundup of other light pillar spottings from around the Greater Toronto Area earlier in the month offers a better idea of how these cold-weather light shows dance over illuminated areas.

One of winter's strangest phenomena made an appearance in the Greater Toronto Area this month. ✨❄️

Have you ever experienced light pillars? @vfennalvarado explains the science behind this fascinating occurrence. pic.twitter.com/Do0b7jiOFg

— The Weather Network (@weathernetwork) January 10, 2022

Light pillars are just one more entry to a growing list of winter curiosities experienced during a bone-chilling January, which has brought walls of sea smoke, pancake ice, and even ice volcanoes.

And that's not to mention the historic blizzard the city is still digging out from almost two weeks later.