Despite plenty of sunshine, bitter cold temperatures Thursday morning will rise only into the teens in the afternoon, according to the National Weather Service.
In contrast to Wednesday, Merrimack Valley schools opened without a delay Thursday morning.
In New Hampshire however, Hampstead, Timberlane, Windham and Derry all have two-hour delays due to the wind chill.
In its forecast Thursday morning, the weather service also warned of slippery road conditions, as "typical road salt is rather ineffective given the currently bitterly cold temps generally ranging from 5 below to 5 above zero."
The weather service said the extreme cold will continue into Friday, with the wind chill making it feel as low as 8 below zero. On Saturday, temperatures will rise to near 32 degrees, the service said.
The forecast for Monday indicates temperatures could reach 50 degrees.