What to wear and when:
In summer Savannah tends to be rather casual except for special events. In winter it's better to err on the more formal side if you're going to a nicer restaurant or private party.
Beware, many streets and sidewalks are old brick or cobble stone and for hundreds of years they've been twisting ankles. (The locals will snicker at tourists stumbling along River Street.)
It can rain like buckets without warning so every apartment has umbrellas for guests.
Below are the average high and low temperatures.