Should I bring a rain jacket?

Only if you are traveling during monsoon season. Otherwise, a lightweight, packable poncho is better; heavy rain gear will just cause you to overheat from the inside.

Will my clothes mold in my bag?

If you leave damp, sweaty clothes in a sealed plastic bag, yes. Use breathable mesh packing cubes and ensure items are fully dry before packing them away.

Packing for Southeast Asia's Heat and Humidity

Stick to lightweight, moisture-wicking natural fabrics like linen or merino wool and pack only enough for 7 days to avoid lugging around heavy, damp clothing. Use compression packing cubes to keep your gear organized and moisture-sealed.

Choose your fabrics carefully. Avoid heavy cotton and synthetics that trap sweat. Opt for 100% linen, bamboo, or light merino wool. These breathe and dry overnight if you need to hand-wash them.
Adopt a 7-day cycle. No matter the length of your trip, pack for one week. You will find laundry services on almost every street corner for roughly $1-2 per kilogram. Dropping off laundry is easier than carrying a heavy suitcase.
Use compression cubes. Use individual compression cubes for your tops, bottoms, and undergarments. This squeezes out excess air, keeping your bag slim and separating clean items from the inevitable damp, worn clothes.
Plan for 'temple modest'. Pack one lightweight pair of loose-fitting trousers and a light scarf or shawl. You must cover your shoulders and knees to enter most religious sites, and these items provide sun protection without the heat.

Should I bring a rain jacket?: Only if you are traveling during monsoon season. Otherwise, a lightweight, packable poncho is better; heavy rain gear will just cause you to overheat from the inside.
Will my clothes mold in my bag?: If you leave damp, sweaty clothes in a sealed plastic bag, yes. Use breathable mesh packing cubes and ensure items are fully dry before packing them away.