Houston, which doesn't typically experience cold weather, has the most stringent guidelines for opening warming centers compared to other Texas cities.

The city only opens warming centers when temperatures dip to 24 degrees for at least two hours. Instead, the Mayor’s Office of Public Safety and Homeland has been coordinating with private facilities.

Though the City of Houston declined to open warming centers during this week's cold snap, several nonprofits are offering resources for Houstonians in need. The big picture: Overnight temperatures must reach 24 degrees (or 15 degrees with a wind chill) for at least two hours for the city to open the centers,