The lineman stated that he noticed ice on the airplane's nose landing gear area and slush-type ice on the wheels but did not look at the airplane's wings. The lineman stated that, while he fueled the airplane, one of its pilots stood near the wingtip. The lineman noted that the pilot seemed to be looking at the underside of the airplane near the right main landing gear but remained near the wingtip and then walked away when the fueling was completed. The lineman assumed the pilot left to go someplace warm because it was cold and "miserable" on the ramp. The lineman stated that fluffy, wet, snow flurries were falling and that he could see to only about the midfield point of the airport due to reduced visibility.