After working late last night, I exited the building on Cedar Street, turned west and saw with startling clarity the lit buildings of the World Financial Center against the blue-black sky. Stark—there’s no better way to describe them there, drawing the eye past the cranes and girders of the World Trade Center site, as if someone had activated a real-world sharpen filter. Is one’s sight clearer in winter? It was harder than I guessed to Google quickly but I found a bad MSNBC article that answers the question:
One reason for the clarity of a winter’s night is that cold air cannot hold as much moisture as warm air can. Hence, on many nights in the summer, the warm moisture-laden atmosphere causes the sky to appear hazier. By day it is a milky, washed-out blue, which in winter becomes a richer, deeper and darker shade of blue. For us in northern climes, this only adds more luster to that part of the sky containing the beautiful wintertime constellations.