New Hampshire safety officials are warning people to prepare for extreme cold Tuesday, with the wind chill in some places forecast to drop as low as 40 degrees below zero.

The National Weather Service has issued a wind-chill advisory from 2 a.m. to 10 a.m. for Cheshire and Sullivan counties, as well as parts of Hillsborough County and many other areas in New Hampshire. Temperatures in those places, accounting for wind, could reach 20 to 25 degrees below zero, the federal agency announced Monday.

NWS also issued a wind-chill warning — indicating a greater threat — starting 10 p.m. Monday for Coos and Grafton counties, where the “feels-like” temperature could be even lower.

In extremely cold conditions, exposed skin could suffer frostbite in as little as 10 minutes, the N.H. Department of Safety said in a news release. Jennifer Harper, the state’s homeland security and emergency management director, said in the release that recommended precautions include staying indoors; wearing several layers of loose-fitting clothing when outside, including a hat, scarf and gloves; and bringing pets inside.

Multiple cold fronts moving through the Northeast early this week are causing the extreme cold, according to Hunter Tubbs, a meteorologist with NWS’ office in Gray, Maine.

“That’s what’s really going to allow Arctic air to pour into northern New England,” he said Monday.

Wind gusts in the region could reach 25 to 30 miles per hour, Tubbs said. That’s unlikely to result in any structural damage but will make the already-low temperatures even more dangerous, he said.

The extreme cold is also impacting operations for several local schools. The Fall Mountain Regional School District, which includes Acworth, Alstead, Charlestown, Langdon and Walpole, announced Monday that all schools in the district will have a two-hour delay Tuesday morning due to the cold. Additionally, the LEAF Charter School in Alstead has a remote learning day due to the weather.

You can find a shelter or warming center near you by calling 211.

Caleb Symons can be reached at 352-1234, extension 1420, or csymons@keenesentinel.com. Follow him on Twitter @CalebSymonsKS.