Do I need a heavy jacket?

Only if you plan to visit northern mountain regions in Vietnam or Laos during December/January. Otherwise, a thin hoodie for air-conditioned buses and planes is plenty.

Can I just buy clothes when I get there?

Yes. Markets are full of cheap, breathable clothing. However, if you are taller or larger than the local average, sizes may be limited, so bring your essentials from home.

What to wear in tropical Southeast Asia

Prioritize loose-fitting, breathable natural fabrics like linen or moisture-wicking synthetic blends to manage extreme humidity. Pack versatile, modest layers that cover your shoulders and knees to comply with temple dress codes while remaining comfortable in 30°C+ heat.

Choose high-wicking fabrics. Avoid heavy denim or thick cotton. Stick to linen, bamboo, or specialized 'tech' fabrics that pull sweat away from your body and dry quickly if you get caught in a downpour.
Respect religious site dress codes. For temples in places like Thailand, Cambodia, or Myanmar, your shoulders and knees must be covered. Carry a lightweight sarong in your day bag to throw over shorts or tank tops when necessary.
Protect your feet. Bring one pair of comfortable, supportive walking sandals (like Tevas or Birkenstocks) and one pair of breathable sneakers. Avoid heavy hiking boots unless you are doing specialized jungle trekking.
Pack a rain shell. Tropical rain is sudden and heavy. A lightweight, packable rain poncho or a thin windbreaker is more useful than a heavy umbrella, which will flip inside out in a storm.

Do I need a heavy jacket?: Only if you plan to visit northern mountain regions in Vietnam or Laos during December/January. Otherwise, a thin hoodie for air-conditioned buses and planes is plenty.
Can I just buy clothes when I get there?: Yes. Markets are full of cheap, breathable clothing. However, if you are taller or larger than the local average, sizes may be limited, so bring your essentials from home.