At least a half-dozen cities notched record high temperature marks as a ferocious January drew to an unseasonably mild close throughout the plains and the Midwest. But more cold weather was lurking to the north. Relatively balmy readings in the mid-40s brought residents out in droves in Boston, with people crowding downtown streets and eating ice cream cones. In Texas, which has seen its share of ice and cold this season, temperatures were in the 70s at Houston. Chicago's lake front blossomed with bicyclists and joggers instead of ice and snow with the temperature at 53, a record for the date. Meanwhile, more arctic cold began to edge its way back into the continental United States from Canada. After a high of 47 at Cut Bank, Mont., temperatures plunged to 7 below zero with a windchill of around 40 below.