How bright is Mercury?
The current visual magnitude of Mercury is 0.60. Given its brightness, Mercury should be visible to the naked eye, easy and bright under dark skyes, might be more difficult from heavily light pollyuted areas.
The following chart is the predicted light curve (visual magnitude as a function of time) of Mercury, according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.