How bright is Mercury?
The current visual magnitude of Mercury is -1.40. Given its brightness, Mercury should be visible to the naked eye, even from highly light polluted 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.
Predicted magnitude of Mercury between January 1600 and December 2499