When rain is possible, choose a costume concept that still works with a weather layer. A bright poncho can fit a traveler, storybook explorer, or color-themed character, while a compact rain jacket may blend into a futuristic or outdoor-inspired look. Check the forecast close to the event and plan for damp ground as well as falling rain. A costume that stays comfortable is more useful than one that only works in a photograph.
Keep important details attached to garments rather than loose accessories. Secure lightweight decorations with stitching or sturdy fasteners, and avoid delicate paper elements if they will be exposed to moisture. A hat with a brim can protect makeup and help define a character, but it should not block your view. Wear shoes with reliable traction, and test the full outfit on a short walk before heading out.
Pack a small repair and comfort kit in a water-resistant pouch. A spare hair tie, a few safety pins, a cloth for drying glasses, and a dry pair of socks can be more helpful than extra decorative pieces. Store electronics and personal items in sealed protection. After the event, hang wet costume pieces to dry fully before packing them away, and check seams, fasteners, and color transfer while everything is still easy to inspect.