Transition in the sky: sunset over Dorchester

Taken from the top floor of the Corcoran Jennison Building on Columbia as the sun set Tuesday just after 4 p.m., this photo captures in stark relief the demarcation of the transition from wet and dark and mild-ish at left to bright and cold in the west and northwest skies at right that will bring temperatures down to the teens and 20s by Wednesday morning.

- Tom Mulvoy