RUGBY, N.D. -- If you've ever wondered what it might feel like to stand at the South Pole, you could have shaved thousands of miles off the trip and headed to North Dakota Tuesday morning instead.
Rugby, North Dakota, which bills itself as the Geographic Center of North America, had a temperature Tuesday morning of -31 degrees with a wind speed of 10 mph. That calculates to a wind chill of -54.
It turns out a weather station on Antarctica near the South Pole was reporting nearly identical weather conditions -- a temp of -31 and a wind speed of 9.5 knots (11 mph).
Back in the Upper Plains, frigid air spread across South Dakota, Minnesota, Wisconsin and Iowa. Duluth's wind chills dropped as low as -40, while the air felt like -27 in Minneapolis and -21 in Green Bay.
Even daytime temperatures remained below zero across much of the region, and sub-freezing temperatures reached as far south as southern Missouri.
The arctic air put on a spectacular display of ice halos and sun dogs across Grand Forks. The tiny ice crystals in the sky refract the sunlight into this incredible light show.
LEARN: What is a Sun Dog?
Wind chills were expected to drop to between -35 and -45 again Tuesday night across eastern North Dakota and western Minnesota, but relatively milder weather was forecast for Wednesday afternoon.