Thessaloniki hosts 1 festival in this guide: Reworks Festival.
Thessaloniki has 1 festival in this guide. They run in September, and festival-day temperatures range from 27°C (81°F) to 27°C (81°F), with nights down to 17°C (63°F). That range is the reason there is no single "Thessaloniki festival outfit". The answer changes by month and by site.
Conditions are moderate across the board, so the day-to-night temperature drop is the thing to plan for rather than the weather itself.
The ground matters as much as the sky. Every festival here is on city streets, which puts broken-in trainers or a low boot at the top of the list for most of these events. None of them have camping on site, so you are travelling in and out each day and the outfit has to survive the journey at both ends.
Stylistically the crowd here leans techno, underground and urban. Reworks Festival is the largest of them at around 20,000 people, and it sets the tone the smaller ones react to. None of that is a dress code. It is what you will see, which is worth knowing if you would rather blend in or deliberately not.
