I was trying to think of nighttime accidents that would not have occurred during daylight hours, and the following easily came to mind:
Bombay AI 747
Windhoek SAA 707
Guam KAL 747
and many others probably.
Now any daytime accidents that would not have occurred at night:
Tenerife maybe? Any others?
Does this indicate that it is considerably safer to schedule one's takeoffs and landings during daylight hours?