(CNN) Record-breaking wintry temperatures are gripping the eastern two-thirds of the country, signaling that this could be one of the coldest seasons in years. Across the United States, 76 locations have shattered their daily record cold high temperatures for December since the beginning of the month. That means some towns saw their coldest December day ever.The bad news is that it's going to get even colder for the rest of the week. Below-freezing temperatures are expected for 7 percent of the country -- in fact, most of the country will see the coldest air since last winter. This storm pattern is reminiscent of the 2014 Arctic outbreak that started a social media trend called the "polar vortex."