Indonesia weather & when to go: January

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

As with its neighbouring Indonesian islands, January is one of the wettest months of the year in Java. Heavy rain and thunderstorms can be expected, especially in the city of Jakarta which is at risk of flooding as the rains peak. Temperatures average 27°C, but can drop to a (relatively) cool 22°C at night. January’s wet weather is not ideal for climbing Mt Bromo or visiting the Ijen Plateau as paths can be slippery and muddy – best to wait for drier conditions.

Bali

The rains continue to fall on the island of Bali throughout January, but although this is typically the wettest month of the year, rainfall is not constant. Expect hot sunny days punctuated with brief, intense downpours and average temperatures of 26°C. Temperatures in the higher central region around Kintamani and Mt Batur are a little fresher and can drop to 15°C at night.    

Nusa Tenggara

Lombok, Flores, Komodo National Park, Sumba

The heavy rains experienced on the neighbouring island of Bali in January are less intense on Lombok & the Gili Islands, Flores & Sumba. However, rain should be expected across the Nusa Tenggara islands and will come in the form of brief intense downpours. Days may be overcast but the average temperature is around 28°C and humidity levels are fairly high. Rough seas during January are not favourable for diving off the coast of Lombok and in the Komodo National Park, and may also cause disruption to inter-island ferry crossings.

Sulawesi

January in Sulawesi is characterised by warm, humid weather, with average temperatures around 26°C and high humidity. Rain and thunderstorms can be expected, especially in the city of Makassar and the southern regions. In fact January is the wettest month of the year across the island. Diving in Manado Bay is best avoided during January as the sea can be rough and visibility will be poor. 

Kalimantan

January is one of the wettest times of the year to visit Kalimantan, 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. Days may be overcast but the average temperature is 26-27°C.

Sumatra

In Medan and North Sumatra the heavy rains of the previous few months start to dwindle in January as they shift their attention to Palembang and the south of the island. It’s worth bearing in mind that January and February tend to experience the heaviest rains of the year in the south which can impact road conditions. Despite heavily overcast skies, temperatures fluctuate around 26-27°C and humidity levels can creep over 80% in the southern regions. 

West Papua & Raja Ampat

January sees sporadic rainfall across the islands of Raja Ampat. However calm seas and good visibility means January is a good time of year for diving. Daily temperatures average 29-31°C. In Wamena and across the Baliem Valley showers can also be expected during the month of January, with average daily temperatures hovering around 22°C.

The Moluccas

January is an excellent month of the year to visit the central Molucca islands. Average temperatures of 28-30°C and dry, sunny days can be experienced on the islands of Ambon and Seram. Elsewhere in the region, on the islands of Kei and Ternate, temperatures remain warm, but rainfall can be expected. Strong winds and rainfall occur in the Banda Islands during January which can affect boat transfers.