How bright is Mars?
The current visual magnitude of Mars is -0.87. Given its brightness, Mars 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 Mars, 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.