Chicago’s largest homeless shelter broke its own rule of accepting only long-term visitors and took in 800 people Tuesday night as the temperature dropped to minus-23 degrees.

The unprecedented number of overnight guests at Pacific Garden Mission came amid frigid temperatures and high winds across the Midwest.

{mosads}Philip Kwiatkowski, the shelter’s president, told the Chicago Sun-Times that extra mattresses were put on the floor to accommodate the “mass of humanity” seeking warmth.

“There’s no restrictions right now,” he said. “We’re letting everybody in.”

The shelter, which has 750 beds for men and 200 for women and children, normally only permits people who plan to stay for 30-day increments.

Record-low temperatures are forecast for Chicago this week, when the city will be colder than Antarctica, Mount Everest and Siberia.

The ride-sharing company Lyft is offering free rides to warming shelters that Chicago opened throughout the city this week.