21 December
Sunrise: 8:25
Sunset: 15:48
7 hours, 23 minutes
I suppose this is the darkest day I've ever seen, since I've never been anywhere further north at this time of year.
If I went due north from here at 54N 2W this is what I'd get. It's interesting to see how once you get to the real subarctic latitudes though the length of the day starts to shorten quite rapidly for each extra degree of latitude you go, the length of the actual night doesn't change anywhere nearly as much due to extended twilight.
55N:
sunrise 8:31, sunset 15:41, day length 7 hours 10 minutes
civil twilight starts 7:45, ends 16:26 (8 hours 41 minutes)
56N:
sunrise 8:37, sunset 15:34, day length 6 hours 57 minutes
civil twilight starts 7:50, ends 16:22 (8 hours 32 minutes)
57N:
sunrise 8:44, sunset 15:27, day length 6 hours 43 minutes
civil twilight starts 7:55, ends 16:17 (8 hours 22 minutes)
58N:
sunrise 8:52, sunset 15:20, day length 6 hours 28 minutes
civil twilight starts 8:00, ends 16:11 (8 hours 11 minutes)
59N:
sunrise 9:00, sunset 15:11, day length 6 hours 11 minutes
civil twilight starts 8:06, ends 16:06 (8 hours 0 minutes)
60N:
sunrise 9:09, sunset 15:02, day length 5 hours 53 minutes
civil twilight starts 8:12, ends 16:00 (7 hours 48 minutes)
61N:
sunrise 9:20, sunset 14:52, day length 5 hours 32 minutes
civil twilight starts 8:18, ends 15:53 (7 hours 35 minutes)
62N:
sunrise 9:31, sunset 14:40, day length 5 hours 9 minutes
civil twilight starts 8:26, ends 15:46 (7 hours 20 minutes)
63N:
sunrise 9:44, sunset 14:27, day length 4 hours 43 minutes
civil twilight starts 8:33, ends 15:38 (7 hours 5 minutes)
64N:
sunrise 9:59, sunset 14:12, day length 4 hours 13 minutes
civil twilight starts 8:42, ends 15:30 (6 hours 48 minutes)
65N:
sunrise 10:18, sunset 13:54, day length 3 hours 36 minutes
civil twilight starts 8:51, ends 15:21 (6 hours 30 minutes)
66N:
sunrise 10:42, sunset 13:30, day length 2 hours 48 minutes
civil twilight starts 9:01, ends 15:10 (6 hours 9 minutes)
67N:
sunrise 11:20, sunset 12:52, day length 1 hour 32 minutes
civil twilight starts 9:13, ends 14:58 (5 hours 45 minutes)
68N:
polar night
civil twilight starts 9:27, ends 14:45 (5 hours 18 minutes)
69N:
polar night
civil twilight starts 9:43, ends 14:29 (4 hours 46 minutes)
70N:
polar night
civil twilight starts 10:02, ends 14:09 (4 hours 7 minutes)
71N:
polar night
civil twilight starts 10:27, ends 13:44 (3 hours 17 minutes)
72N:
polar night
civil twilight starts 11:05, ends 13:06 (2 hours 1 minute)
73N:
polar night
no civil twilight
Sunrise Sunset Times