Bali is in its dry stretch right now, May to October. This is the easy window: plan around sun and heat rather than around rain.
Going in July
The dry season, and the reason the island is busiest from June onwards: less rain, lower humidity and reliably cooler nights.
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 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 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 pack
Build a packing plan around the season you are actually travelling in.