It is rainy season in Colombo & the southwest right now, and it runs May to September. The rain tends to come hard and short rather than all day, and it stays warm through it — so the thing to bring is a shell you can fold into a day bag, not a coat.
Going in April
The dry, settled half of the year on this coast — and the reason the southwest is the high season while the east is closed.
What this means for your bag
Real sun protection
High-factor sunscreen, a hat with a brim and sunglasses. Reef-safe sunscreen is worth buying before you go — it is expensive and hard to find at the beach.
See the Beach & Pool Kit packRoom for humidity
Everything stays slightly damp. Pack fewer clothes and plan to wash them, and keep anything that must stay dry in a sealed bag.
See the Summer Sun Kit packQuick-dry fabrics
Cotton takes two days to dry in this air and starts to smell before it does. Synthetics and merino wash in a sink and are wearable by morning.
See the Summer Sun Kit pack
Build a packing plan around the season you are actually travelling in.