The climate of a location or region is affected by its latitude, altitude, terrain, and nearby water bodies and their currents. There is variation in climate across different parts of the world. These variations are mostly due to natural processes or external factors such as persistent changes to the atmosphere or changes in land use.

Taking a closer look at Indonesia’s climate, the main variable is neither temperature nor air pressure, but rainfall. There are extreme variations in rainfall, especially when comparing the dry season (June to September) to the rainy season (November to March). Indonesia’s climate is mostly tropical and temperature does not vary much from season to season. It should be noted, however, that climate is not temperature. Climate is an entity on its own while temperature is a variable of climate; other variables include humidity, precipitation, cloudiness, visibility and, wind.

There are three different climates that can be found in Indonesia. The primary climate in Indonesia is tropical rainforest, which has the highest level of precipitation, followed by tropical monsoon and tropical savanna which have lower levels of precipitation. The western and northern parts of Indonesia have the most precipitation.

Elevation has a major impact on the climate. As elevation increases, pressure decreases. As pressure decreases, air molecules spread out further leading to a decline in temperature. The lowest point in Indonesia is in southern portion of the Philippine Trench, east of Miangas. It is 9,125 meters below sea level. The highest point in Indonesia is Puncak Jaya at 4,884 meters above sea level. Indonesia has a mean elevation of 367 meters above sea level.

Seasons in Indonesia

The wet and dry seasons are the two major seasons experienced in Indonesia, and the climate differs across its various islands. The west coast of Sumatra gets above 400 centimeters of rain per year. Other islands that receive much rain include Kalimantan, Java, Papua, and some parts of Sulawesi, while islands such as Sumba and Timor receive less rain. Therefore, West Sumatra, West Java, Bali, Central Kalimantan, Sulawesi, and Papua are the most damp regions of Indonesia with rainfall totaling 2,000 millimeters a year.

Indonesia shares land borders with Papua New Guinea, East Timor, and the eastern part of Malaysia. Other countries which are also close to Indonesia include Singapore, Vietnam, the Philippines, Australia, and Palau. India’s Andaman and Nicobar Islands are also near Indonesia. The climate of Indonesia and its neighboring countries are mostly alike because there are similarities in the times of year that seasons occur. Furthermore, most of these countries experience tropical climates as well. However, Indonesia’s abundance of islands leads to a clear-cut difference between its rainy season and dry season – something which does not exist in other neighboring countries.

Indonesia is the world’s largest archipelago. It is comprised of approximately 17,500 islands. Indonesia is considered to be at serious risk from projected effects of climate change. It is predicted that unreduced emissions will see an average temperature rise of around 1°C by mid-century and the frequency of extremely hot days (temperatures higher than 35°C) per year will almost double by 2030. This is a figure which is predicted to further rise by the end of the century, thereby affecting businesses. This will raise the frequency of droughts and food shortages and change the precipitation patterns of the wet and dry seasons.

Indonesia is south of the typhoon belt which includes the Philippines, Vietnam, China, and Japan. Since Indonesia is close to the equator and surrounded by much water, its climate is a tropical marine climate with light winds and frequent thunderstorms. Monsoon winds and mountains also affect Indonesia’s climate. Temperature and rainfall vary across its different islands due to elevation and monsoon patterns. The dry season is mainly influenced by the Australian continental air masses while the wet season is influenced by air masses from mainland Asia and the Pacific Ocean.

Taking into consideration Indonesian climate, it is best for tourists to visit between May and September. At this time, there is less rain, more sunny days, and offshore winds on the west coast. On the other hand, the wet season has high temperatures and intense rainfall lasting multiple hours every day. Generally speaking, travelling to Indonesia is possible all year round.

Some regions like Bali, however, do not have a noticeable difference in the two seasons. It should be noted that there are greater chances of flooding during the wet season. This is a major problem faced by Indonesians as floods times restrict business activity and economic output due to the heavy downpours. The weather in Bali is suitable for travel all year round, a fact that should be noted by prospective travelers. Bali is situated approximately eight degrees south of the equator.

Indonesia and Climate Change

Due to the effects of global warming and climate change all over the world, weather in Indonesia can often be unpredictable. There may sometimes be rain during the dry season or dry spells during the rainy season. There are many variations in climate pertaining to each island such as Sumatra, which experiences rain from October to January in the north and November to February in the south. Sulawesi also experiences slightly different weather patterns across the island; rainfall can be expected in the northern regions of the island during June and July.

Bali and Kalimantan are relatively unaffected by seasonal weather changes, but they face greater chances of flooding and droughts during the wet and dry seasons respectively.

Climate has affected Indonesia in several ways due to the extremes of both seasons. Jakarta, the capital of Indonesia, is the most vulnerable city in Southeast Asia to the impact of climate change. According to Mariah Measey, “Indonesia is the third largest emitter of greenhouse gases in the world, which is the primary cause of global climate change.” This is mainly due to the large population and vast economic growth of Indonesia. These have the effects of causing not only global warming but also the rising of sea levels.

Indonesia is very vulnerable to climate change hazards due to its geographical location, tropical climates, and the fact that it is an archipelago. Climate change hazards are important to Indonesia because its Gross Domestic Product is largely dependent on agriculture. Indonesia also has limited capacity to adapt to hazards because it is a developing country. It is at high risk of sea level rise, flooding, and landslides. It has been found that sea level rise due to global warming in the coastal areas of Indonesia is currently around three to five millimeters per year. The annual mean temperature has increased by about 0.3°C since 1990 and the annual precipitation has decreased by 2-3%. In the south of Indonesia, there has been a decline in precipitation while in the north, there has been an increase in precipitation. The temperature is projected to increase evenly across all of Indonesia by 0.1-0.3°C per decade.

Due to the fast rate at which climate is changing in Indonesia, there will be some substantial negative impacts. The rising of the sea level will result in the loss of Indonesia’s coastline, islands, and associated marine resources. There will be changes in the intensity and pattern of rainfall and these changes will cause a wetter climate in Sumatra and Kalimantan but drier seasons in Java, Bali, and Nusa Tenggara. Decreased rainfall during dry seasons may increase drought risks and rainfall during wet seasons may increase flood risks. Floods have substantial impact on the population, causing displacement of people from their homes, traffic chaos, and interruption of daily business activities. One such example was the flood that took place in Jakarta in 2015. This resulted in economic loss, death, and damage to properties and infrastructure.

Indonesia’s rapid industrialization and high population present environmental issues which are not prioritized due to high poverty levels and an underdeveloped government. Issues such as illegal large-scale deforestation and related wildfires, overexploitation of marine resources, traffic congestion, garbage mismanagement, and rapid urbanization have caused drastic impacts on the climate. Industrial pollution is increasing, particularly in Java, and the natural resources of the Indonesian archipelago have been overexploited.

The enormous coastal population is at risk of the effects of climate change. The livelihood of many of Indonesia’s citizens depends on agriculture, mariculture, and fishing. These could be impacted by temperature, rainfall, and other climatic changes. Indonesia is one of the largest emitter of greenhouse gases which damage the environment. There have been recent changes in rainfall patterns in Indonesia. These changes were predicted to have an adverse impact on agriculture due to shorter rainy seasons. Indonesia experienced crop losses and fish losses as a result of climate change as early as 2007. These losses brought about a disruption in economic activities as agriculture is the primary source of income for many in the country.

The response to global climate change includes mitigation and adaptation. Even though Indonesia is taking steps towards mitigation and adaptation, the country still has a long way to go. The major problem is the general lack of coordination and connection between the different bodies involved. There is a need to rectify this problem to improve the country’s level of adaptation.