It's so cold in Finland right now that Celsius and Fahrenheit are the same

• It's really, really, really cold in Finland and Sweden right now.
• It's so cold that Celsius and Fahrenheit are the same. 
• That's minus 40 degrees. No thank you.

Finland and Sweden recorded their coldest temperatures of the winter Tuesday when thermometers plummeted as low as minus 40 degrees Celsius (minus 40 Fahrenheit) as a cold spell grips the Nordic region.

Cold and snow disrupted transportation throughout the region, including in Norway where a major highway in the south was closed due to the weather and ferry lines suspended operations. Swedish train operators said the cold snap caused substantial problems for rail traffic in the Arctic north.

Nikkaluokta, a small village inhabited by indigenous Sami people in northern Sweden, recorded a temperature of minus 41.6 degrees C (minus 42.8 F) early Tuesday, Swedish public broadcaster SVT reported.

"It's the coldest temperature we have had so far this winter, and it will continue to be quite cold weather in the north," SVT meteorologist Nils Holmqvist said.

The Swedish Meteorological and Hydrological Institute reported temperatures of minus 30 C (minus 22 F) in several locations in northern Sweden, and issued a warning for snow and wind for central and southern Sweden. Its second-highest warning applies from midnight into Wednesday.

In neighboring Finland, this winter's cold record was recorded in the northwestern town of Ylivieska where temperatures fell to minus 37.8 C (minus 36 F) early Tuesday, and forecasters said temperatures would be lower than minus 40 C in parts of the nation through the week.

Temperatures in the Finnish capital, Helsinki, were expected to hover between minus 15 and minus 20 C (around zero F).

In the southern Norway town of Arendal, officials said schools would be closed Wednesday because it wasn't possible to clear the sidewalks in time for children to get to school.

Several ferry companies throughout the region canceled crossings, including those from southern Norway to Denmark where a key bridge was closed to vehicles with light trailers because of strong winds, Danish officials said.