No mail will be delivered to parts of 10 states as polar vortex chills postal delivery

So much for "Neither snow nor rain nor heat nor gloom of night." The U.S. mail won't be delivered Wednesday in large swaths of at least 10 states due to the crippling cold of the polar vortex.

The USPS announced that no mail will be delivered in parts of Michigan, Iowa, Minnesota, North and South Dakota, Wisconsin, Illinois, Indiana, Ohio, and Pennsylvania. Some retail offices of the postal service will be open, but couriers won't be delivering any mail to those areas.

It's not the first time that mail carriers won't deliver mail to certain addresses due to bad weather, but typically, those scenarios happen on a street or two that is blocked off by snow drifts. In Wednesday's case, it is the forecast for extreme cold, which is hitting the Midwest particularly hard.

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On Wednesday, Chicago will be colder than parts of Antarctica, Alaska and the North Pole, and scores of schools, city halls, businesses and even zoos will be closed across the region.

The Windy City's "high" temperature on Wednesday should be around 10 below zero, while the overnight low Wednesday night into Thursday morning is forecast to be in the 25-below range, according to the National Weather Service in Chicago.

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But even with the lack of mail delivery Wednesday, there's no real breach of a postal service motto. While many people believe that "Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds" is an official motto for the postal service, it is not.

According to the USPS, "While the Postal Service has no official motto, the popular belief that it does is a tribute to America's postal workers. The words above, thought to be the motto, are chiseled in gray granite over the entrance to the New York City Post Office on 8th Avenue."

The words, according to the USPS, "come from Book 8, Paragraph 98, of The Persian Wars by Herodotus. During the wars between the Greeks and Persians (500-449 B.C.), the Persians operated a system of mounted postal couriers who served with great fidelity."

While the postal service does not have an official motto, it does have an official mission statement:

The Postal Service shall have as its basic function the obligation to provide postal services to bind the Nation together through the personal, educational, literary, and business correspondence of the people. It shall provide prompt, reliable, and efficient services to patrons in all areas and shall render postal services to all communities.

There's no word yet on when mail service will resume in the affected regions.