Month may become dimmest on record Since the sun virtually disappeared on June 5, hidden behind an impenetrable pall of cement-coloured clouds, Robert Skilling has tracked each overcast moment, anticipation building with each grey afternoon. Peering out at the gloom from his perch at the Blue Hill Meteorological Observatory and Science Centre, Skilling does not dwell on the cancelled Little League games or postponed beach days. Rather, he focused yesterday on the primitive, softball-sized glass sphere on the observatorys roof, a device that has burned lines on paper since 1885 to record nearly every burst of sunshine strong enough to cast a faint shadow. This month, the sun has been obscured by clouds more than in any other June in Skillings 50-plus years of meteorology. With a little more than a week remaining, it is flirting with the all-time local record set in June 1903, when only 25 percent of the suns rays penetrated the clouds to reach the Blue Hills.