The effects of real-world time, date and moon phase in NetHack 3.4

time-341.txt Last edited 2003-03-09 for NetHack 3.4.1
Compiled for 3.1.3 by Boudewijn Waijers.
Edited for 3.4.1 by Dylan O'Donnell <>.
HTML Conversion by Kate Nepveu.


NetHack is aware of the time in the real world (or, at least, what it's told about it by your system clock); certain particular times have effects on gameplay.

Moon phases and dates

The date is only checked when the game is started or restored; if you keep playing without saving, you'll continue to see the effects even after the relevant period has passed (or not see the effects even though it has been reached). NetHack divides the month into eight phases of three or four days each; thus the full and new moon will be reported for a rather longer time than your calendar might depict.

Full moon:

New moon:

Friday the 13th:

If Friday 13th happens to be a full moon, the -1 and +1 to baseline luck will cancel out. See gems-341.html for more discussion of how luck is calculated.


Night (22:00 - 05:59):

Midnight (0:00 - 0:59):

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