Indonesia weather & when to go: December

NB: the westernmost point of Indonesia is a full 3200 miles from the eastern most tip, so it should come as no surprise that summarising the weather is not straightforward. The tables above split the ‘country’ (made up of 17,508 islands) into two regions - the western & central islands and the eastern islands (that sit to the east of the Wallace Line), however we encourage you to read the more detailed summaries below as there can be significant variations in conditions between the islands within each group.

Java

Wet season arrives into Java. December is one of the wettest months of the year, characterised by heavy rain and thunderstorms, especially in the city of Jakarta which is at risk of flooding. Surabaya and East Java experience slightly fewer rainy days, but are still prone to intense downpours. Average temperatures drop slightly to 27°C.

Bali

The rainy season is in full swing across Bali throughout December, although it is not constant and intense bouts of rain are punctuated with hours of sunshine. Average temperatures remain around 27°C. It can be windy around the south coast beaches of Jimbaran, Sanur & Seminyak and sea conditions can be rough.

Despite the weather, the weeks around Christmas are a busy time of year to visit Bali and there's an air of celebration and excitement on the island. 

Nusa Tenggara

Lombok, Flores, Komodo National Park, Sumba

Wet weather continues across Lombok & the Gili Islands, Flores & Sumba throughout December, although rainfall is not constant and intense bouts of rain are punctuated with sunshine. Average temperatures hover around 28-29°C, with frequent highs of 32°C. Humidity levels are particularly high on the island of Lombok and can reach 85%, whilst in Sumba conditions are slightly more comfortable with chance of a light breeze. 

Kalimantan

Heavy rain continues throughout Kalimantan in December, with rainfall occurring in the form of intense downpours, however the rains are not as heavy as in other neighbouring islands such as Java at this time. Average temperatures remain around 27-28°C. 

Sumatra

Wet season continues across the island of Sumatra in December, although the rains start to dwindle in Medan and the northern regions towards the end of the month. It’s worth bearing in mind that journeys may take longer at this time, as road conditions can be affected by the rain. North Sumatra is slightly cooler than the south, although average temperatures still hover around 27-28°C, and humidity levels can climb above 80% in the north.

Sulawesi

December is one of the wettest months of the year across Sulawesi, with monsoon season in full swing in Toraja and the south. Diving in Manado Bay is best avoided during December as the sea can be rough and visibility will be poor. Days may be overcast but the average temperature is around 28°C and humidity levels are high. 

The Moluccas

The year ends much as it began, with warm (28-30°C), dry, sunny days being enjoyed across the central Molucca islands; whilst the southern islands of Kei and Aru, and the northern islands of Ternate and Tidore are experiencing overcast skies and rainfall during December. Strong winds and rainfall occur in the Banda Islands during December which can affect boat transfers.

West Papua & Raja Ampat

December sees sporadic rainfall across the islands of Raja Ampat and throughout the Baliem Valley. However calm seas and good visibility makes December a good time of year for diving. Average day time temperatures remain consistently warm during December.