With the long, hot days of summer not past us just yet, this week’s gray skies and dripping rain made many Washingtonians pine for the sunnier season that always seems to end too soon. This photo, of Rio King, 2, his brother Mattias, eight months, and their dog, Riker, seemed to conjure up exactly that longing. The boys and their mother, Heather, were on a walk on a particularly nice morning in the Congressional Cemetery. A group of dog walkers on Capitol Hill, the K-9 Corps, pay fees to use the historic cemetery’s grounds as an off-leash dog park. The arrangement allowed Riker to walk unfettered as the boys stopped for a quick break.