Crepuscular

adj.

1 : of, relating to, or resembling twilight : dim <crepuscular light>
2 : occurring or active during twilight <crepuscular insects> <crepuscular activity>

[Merriam-Webster]

Via Nico Muhly, on London in February:

"When the light hits just right, which, in winter is several crepuscular hours, a walk through that area is unrelentingly beautiful."

See also: Thelonious Monk, "Crepuscule with Nellie." [via @terryteachout]