Weather in Indonesia in September

September in Indonesia typically marks the transition from the dry season towards the onset of the wet season in some regions. Travellers can expect warm temperatures throughout the country, with variations in rainfall and humidity levels. This month often provides favourable conditions for exploring the vibrant landscapes and engaging in various outdoor activities.

September Climate Overview

• Average Temperature: 24°C – 32°C
• Rainfall: 60mm – 130mm
• Sunshine Hours: 8 to 9 hours per day
• Sea Temperature: 28°C
• Humidity: 75% – 85%
• Wind Speed: 10 km/h – 15 km/h

What to Expect in September

Daytime Conditions

During the day, Indonesia experiences warm and relatively stable temperatures with highs often reaching above 30°C. The sun is usually bright, although the humidity can make it feel hotter. It’s a great time for sightseeing but staying hydrated and protecting against the sun is recommended.

Rainfall Patterns

Rainfall in September can be inconsistent, with some areas experiencing scattered showers, while others remain relatively dry. The rain generally occurs in short bursts and is not expected to significantly affect outdoor plans, making it a convenient time for excursions.

Evening Conditions

Evenings bring cooler temperatures that are more comfortable, often accompanied by gentle breezes. Humidity levels may remain high but do not deter enjoying outdoor dining or exploring nightlife, offering a pleasant end to the day.

Best Activities in Indonesia in September

• Outdoor Activities: Hiking in national parks, visiting local markets, and touring historical sites are ideal due to the generally favourable weather conditions.
• Seasonal Highlights: September is an excellent time to observe local harvests and enjoy the lush landscapes coming to life after some refreshing showers.
• Water-based or Nature-based Activities: With pleasant sea temperatures, diving and snorkelling remain popular activities in coastal areas.

What to Pack for September

• Light, breathable clothing for daytime and slightly warmer layers for the evening.
• Sun protection such as a hat, sunglasses, and sunscreen, or a light raincoat for unexpected showers.
• Comfortable footwear suitable for walking or hiking.
• A reusable water bottle to stay hydrated in warm and humid conditions.