Toronto's night sky was painted in a haunting yellow glow this weekend, and many took to social media with photos of the strange phenomenon seeking an explanation.

Photos captured from various points in the city on Saturday and Sunday nights show a bright yellow cast reflected off of clouds.

Why is the sky in Toronto so orange and bright three hours after sunset. I feel like I’m walking into the apocalypse right now pic.twitter.com/m34SCDC6cs

— Emma McIntosh (@EmmaMci) February 11, 2024

Many were confused by the multi-night glow, taking to social media for answers.

Ok Twitter what is this creepy light in Toronto sky mean? pic.twitter.com/n3rbHXPD7e

— Nahum Mann (@nahum_mann) February 12, 2024

One user offered up a hilarious but not-at-all-serious explanation.

there's a strange glow in the sky above west toronto tonight...only a blood sacrifice by one of our 351 weed dispensaries will appease the gods pic.twitter.com/jB6dnFPIl4

— Jonathan (@jtalms) February 12, 2024

Others searched for the best spot to view the phenomenon.

Tired, but climbed the Wallace bridge to see mystery sky glow#Toronto pic.twitter.com/xvd0177RbX

— Celadon Cat of Tw*tter 🇨🇦 🇱🇹 🇺🇦 (@Celadon_kate) February 12, 2024

So what is the mystery all about?

#topoli What’s the latest theory about GlowTO? pic.twitter.com/VtY75nY4Vz

— John Lorinc (@JohnLorinc) February 12, 2024

It turns out that the mysterious new glow is actually neither mysterious nor new, as this phenomenon has been spotted several times over the years.

BMO Field's grow lights pictured shortly after the stadium was expanded in 2016. Photo by Jack Landau.

The explanation? This yellowish light cast into the sky is the result of ultra-bright grow lights used at BMO Field to promote grass growth and keep the stadium's hybrid playing surface in peak condition through Toronto's harsh winters.

BMO Field's grow lights pictured after dark in 2022. Photo by Jack Landau.

BMO Field's occasional nighttime glow has only increased in intensity in the years since these reports first began to flood in. The stadium was already painting the night sky yellow before even more lights were added a few years ago, adding to the otherworldly effect.

A weird glow in the sky, Toronto west side. At first I thought it was a fire. It's been happening all week and I just read it's the BMO soccer field. Apparently every February they use grow lights at night to grow the turf. pic.twitter.com/p4GaMvLpZ3

— Sook-Yin Lee (@sookyinlee) February 12, 2024

The stadium introduced additional grow lights to help maintain its natural grass surface in 2019, and now utilizes nine large mobile lighting rigs and an additional six smaller rigs that can cover 65 per cent of the field in artificial light and heat.

BMO field’s got its grow lights on tn, lighting up the west end sky with an orange glow! You can barely tell it’s midnight in this photo with how bright they are! #Toronto pic.twitter.com/ORIZc6XA38

— Eric McElroy (@esmcelroy) February 12, 2024

BMO Field will host the Toronto FC home opener on Saturday, March 9 at 2 p.m., when the club squares off against Charlotte FC.