what is the off season at Universal orlando, where it is the least busy.

Typically because of weather and school the fall

March to May

Early way early

Check their web site, generally the best source for that info

Before spring break and after school starts in fall

Jan - May. Aug - Sept. Stay away from Holidays, Spring Break, Summer

February

September October gets busy again with HHN then Jan-March

January thru March is the least crowded. Never more than a 10 minute wait on any rides

Early spring when Florida schools are in session.