Indonesia straddles the equator and has two seasons: dry (roughly May to September) and wet (October to April). But the timing and severity varies enormously across the archipelago — when it is raining heavily in Bali, it may be dry and clear in eastern Indonesia, and vice versa.
The dry season (May–September) is the most popular time to visit and generally the best. Skies are clearer, roads are passable, and the sea is calmer for diving and island-hopping. June and July are peak season — prices rise, Bali gets crowded, and accommodation fills up early. May and September offer the same good weather with fewer tourists and lower prices.
The wet season (November–March) brings afternoon downpours most days, high humidity, and occasional flooding. For much of Java and Bali, this means a few hours of rain in the afternoon and clear mornings — still perfectly possible to travel, and the landscape is brilliantly green. Prices drop significantly and the tourism crowds thin out.
Specific timing: - For diving at Komodo, the best visibility is in the dry season. The Komodo dragons are present year-round. - For orangutans in Kalimantan or Sumatra, the dry season is better for trekking through the jungle. - For surfing in Bali, the southwest swell peaks June to August. - For the Tana Toraja funeral season in Sulawesi, most ceremonies are held June to August. - For Bali's Nyepi (Hindu New Year), this falls in March or April — a unique experience, but book accommodation well in advance. - For the Tengger Kasada ceremony at Mount Bromo, this is held at full moon in June or July.
Ramadan is observed across most of the country. During the fasting month, food stalls are closed during the day in many areas and nightlife is quieter. Idul Fitri at the end of Ramadan triggers the largest domestic migration in the world — book transport weeks ahead if you need to travel at that time.
The Java–Bali route is worth doing year-round. Eastern Indonesia (Maluku, Raja Ampat, Nusa Tenggara) is more weather-dependent — plan around the dry season.