Another round of sweltering heat is in store for much of the U.S. this week. The National Weather Service predicts that more than 90 temperature records across the U.S. will be tied or broken this week through Wednesday. Most of those will be overnight heat records. Health experts say that overnight temperatures that fail to cool down are even more dangerous than when daytime temperatures soar. Over the next few days, cities in the Midwest and Northeast known for more record-breaking cold are likely to see record-setting nighttime temperatures. Those include Fargo, North Dakota; International Falls, Minnesota; and Portland, Maine.