St. Augustine is a very safe town.  Most crimes are small property crimes and often perpetrated by outsiders who prey on tourists up and down the coast.  There is a transient homeless population (if you have to be homeless, you might as well be warm...) and sometimes they commit crimes of opportunity against unlocked cars, purses left on car seats, etc.

 St. Augustine is a sunny place which can become quite hot in the summers.  Visitors should be aware of the risks of heat exhaustion and heat stroke.  These risks are not high and are unlikely to be a problem for most travelers.  Making sure to stay in the shade, drink a lot of water and wear sunscreen are all things which reduce the likelihood of being harmed by the sun during a trip to the area.  When visiting the areas fine beaches, know how to react to rip tides which are known to occur up and down the Atlantic coast.  Also, be aware of the colored flags at the beaches.  Red flags indicate hazardous surf, and purple flags indicate the presence of hazardous marine life, such as jellyfish.