The average high temperature in Big Sur in March is 64 degrees Fahrenheit and the average low temperature is 41 degrees Fahrenheit. However, it is not unusual for temperatures to dip below freezing at night, so be sure to pack appropriate clothing if you are visiting during this time of year. March is also the rainiest month of the year in Big Sur, so be prepared for wet weather if you are visiting during this time. However, the rains often bring with them lush and beautiful scenery, so don't let the chance of a few showers deter you from enjoying all that Big Sur has to offer.