First timer - NOT CAMPING, will it be cold during the last sets?

Hi all,

Researching about what to wear, I know it gets hot during the day and chilly at night… but I see most people warning others to stay warm at night sleeping in their tents. I am not camping, does it immediately get cold when the sun goes down? Will I need a good jacket to watch the last sets and exit? For reference, I am from FL so anything below 75 is cold for me.