September weather forecast
Indonesia

September in Indonesia signals the gradual transition from the dry season to the wet season. However, most parts of the country still enjoy predominantly dry conditions during this month. The average temperature remains consistent, generally fluctuating between 23°C (73.4°F) and 28°C (82.4°F). In high-altitude regions, such as the highlands of Papua and the mountains of Sumatra, temperatures can be slightly cooler.

When it comes to rainfall, September marks a transitional period. For example, Jakarta typically receives about 50mm (1.97") of rainfall, which indicates a slight increase from the preceding dry months. Likewise, Bali experiences a modest increase in rainfall with an average of approximately 60mm (2.36").

Comparing September to August, there's a minor increase in the amount of rainfall as the country slowly transitions towards the wet season. As the country moves into October, the trend of increasing rainfall continues, with western and central parts of Indonesia experiencing more frequent showers.

Travelers visiting in September can still expect mainly dry and sunny days, but should be prepared for the possibility of occasional showers, especially towards the end of the month. Despite the onset of the wet season, September can be an attractive month to visit as the landscapes remain vibrant and lush, while tourist crowds start to thin out after the peak travel season. However, as always, caution is advised in areas prone to flooding or landslides as rainfall increases.

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• Jakarta - September »
  In September, the average sea temperature is 29°C (84.2°F). In Jakarta, in September, during 13.5 rainfall days, 46mm (1.81") of precipitation is typically accumulated.
• Surabaya - September »
  On the first day of September in Surabaya, Indonesia, sunrise is at 05:29 and sunset at 17:28. Surabaya's weather in September heralds the dry season's final phase with significantly less rainfall compared to the early months of the year.
• Bandung - September »
  September and October, with an average relative humidity of 81%, are the least humid months in Bandung, Indonesia. The months with the most sunshine in Bandung, Indonesia, are August and September, with an average of 8.5h of sunshine.
• Medan - September »
  The average relative humidity in September in Medan, Indonesia, is 77%. On the first day of September in Medan, sunrise is at 06:19 and sunset at 18:30.
• Bekasi - September »
  In Bekasi in September, it is raining for 11.8 days, with typically 46mm (1.81") of accumulated precipitation. On the last day of September, in Bekasi sunrise is at 05:36 and sunset at 17:46 WIB.
• Palembang - September »
  The least humid month in Palembang is September, with an average relative humidity of 73%. September is the least humid month in Palembang, with an average relative humidity of 73%.
• Tangerang - September »
  As September unfolds, Tangerang's rainfall begins a slow ascent, paralleling the gradual increase in temperature to 30.7°C (87.3°F). On the last day of September, in Tangerang, sunrise is at 05:38 and sunset at 17:48 WIB.
• Makassar - September »
  August and September are months with the least rain in Makassar, Indonesia, when the rain falls for 8.1 days and typically aggregates up to 19mm (0.75") of rain. In Makassar, during September, the rain falls for 8.1 days and regularly aggregates up to 19mm (0.75") of precipitation.
• Semarang - September »
  September is the least humid month in Semarang with an average relative humidity of 81%. In Semarang in September, the average water temperature is 28.6°C (83.5°F).
• Depok - September »
  With an average relative humidity of 70%, September is the least humid month in Depok, Indonesia. In Depok, during September, the rain falls for 10.7 days and regularly aggregates up to 22mm (0.87") of precipitation.
• Batam - September »
  The month with the least rainfall in Batam is September, when the rain falls for 20 days and typically collects 58mm (2.28") of precipitation. In Batam during September, the rain falls for 20 days and regularly aggregates up to 58mm (2.28") of precipitation.
• Pekanbaru - September »
  September in Pekanbaru observes a rise in rainfall, up to 210mm (8.27"), denoting the gradual inauguration of the second monsoon phase. With the arrival of September, Pekanbaru transitions to an average high temperature of a still tropical 31°C (87.8°F), nearly identical to August's weather.