Port of Spain hosts 1 festival in this guide: Trinidad Carnival.
Port of Spain has 1 festival in this guide. They run in February, and festival-day temperatures range from 32°C (90°F) to 32°C (90°F), with nights down to 23°C (73°F). That range is the reason there is no single "Port of Spain festival outfit". The answer changes by month and by site.
Every one of them runs in real heat (28°C or more), where loose natural fabrics beat coverage and a brimmed hat does more than any garment.
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 carnival, costume, parade and tropical. Trinidad Carnival is the largest of them at around 500,000 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.
