Upcoming dividends, if any, will affect the option price.
Volatility changes will affect option prices as well. For e.g. if there is an announcement due that could cause a gap/volatile move, prices/implied volatilities will go through the roof.
Notice in this volatility chart that IVs raced higher well before the actual realized volatility. This was due to an impending announcement that did move the stock big time, as expected. (although did underestimate the move)