The best time to visit Indonesia

What a year in Indonesia looks like

Indonesia sits on the equator with two main seasons, dry and wet, but their timing differs island to island. Bali and Java are dry roughly May to September, which is when most visitors come, while the eastern islands and parts of Sumatra run to a different rhythm. Temperature barely moves across the year; what changes is rainfall and the state of the sea.

The year, in windows

• May to September (Bali and Java) — The dry season: sunny, a calm sea and the best underwater visibility. It is also when room rates peak and Bali's main roads are busiest, with July and August the fullest.
• October to November — A shoulder window where rain returns but is not yet continuous. Prices drop from the peak and crowds thin noticeably — the best value of the year if you can live with an afternoon shower.
• December to March — The wet season on Bali and Java. Rain tends to fall hard in the afternoon and at night rather than all day, the sea gets rough and fast boats between islands can be cancelled. Rates are at their lowest except for new-year week.

The weeks to aim for

May and September give dry-season weather with fewer people than the middle of it. If diving is the point, follow the dry season of the specific island you are heading to — the eastern ones keep their own calendar.

The weeks to avoid

New-year week prices run high against the wet season, and national holidays fill domestic flights. If your trip involves several connecting flights, avoid those weeks or book further ahead than usual.

What the season does to a data plan

Coverage is good in the cities and the main visitor areas of Bali and Java, and in the larger towns on other islands; on small and remote islands it can be limited to the village area. The wet season affects power and hotel Wi-Fi more than the mobile network. Download maps before every boat crossing.