Trades/Field roles (construction, oil & gas, logistics): Clean, neat casual wear is usually fine unless told otherwise — the interview isn't the job site, so no need for full PPE, but avoid anything overly casual like flip-flops.
Healthcare: Business casual, conservative, comfortable — you may be asked to demonstrate mobility/tasks.
General rule: When unsure, dress one level more formal than you think the job requires. It's easier to be slightly overdressed than underdressed.
Guyana's climate: Lightweight, breathable fabrics are practical — but keep it polished, not beach-casual.