The greatest brilliancy actually occurs on the 21st, but Venus has magnitude at least -4.5 all month. This makes it visible before sunset if you know where to look. Since the earth reaches its perihelion every January, we are unusually close to Venus. All this happy geometry only happens once every eight years.
Some people claim to be able to detect the crescent phase of Venus without optical aid.
It is certainly obvious in the smallest telescopes and even good binoculars. Its cause is unknown. The bright giant planets are also interesting this month, Although Jupiter and Saturn are beginning to lose some of their brilliance, they are still well-placed high in the south just after sunset. The pair will not fit together in a binocular field again for almost twenty years. The moon passes just under them the first two evenings of the month.