Schedule of Shadowless Days in Indonesia September-October 2026
The Shadowless Day phenomenon will occur again in several regions of Indonesia in the second half of 2026. This astronomical event takes place when the Sun is directly above a location, causing the shadow of a vertical object to disappear momentarily.
The timing of Shadowless Day differs in each area. The Meteorology, Climatology, and Geophysics Agency (BMKG) has published the schedule for the second main culmination in various provincial capitals, which can serve as a reference for the public to observe it.
What Is Shadowless Day?
Shadowless Day, also known as the main culmination or solar transit, is a phenomenon when the Sun is at its highest position in the sky. During the main culmination, the Sun is directly above the observer’s head or reaches the zenith point.
In this condition, the shadow of a vertical object can appear very short or even seem to disappear because the Sun is directly above the object. This phenomenon can occur in Indonesia because the country is located around the equator.
When Does It Occur in Indonesia?
BMKG explains that the main culmination occurs when the Earth’s equatorial plane is not exactly aligned with the ecliptic plane. The apparent position of the Sun from Earth then continues to change throughout the year, ranging from about 23.5 degrees North Latitude to 23.5 degrees South Latitude.
In 2026, the Sun will pass over Indonesian territory in two periods. The first main culmination takes place between 21 February and 5 April, while the second main culmination occurs between 21 September and 21 October. It is this second main culmination schedule that covers a number of provincial capitals in September and October 2026.
To observe Shadowless Day, the public can prepare a vertical object such as a stick placed on a flat surface. Observation can be carried out close to the culmination time listed in the schedule, taking into account weather conditions in each area.
Schedule in Each Provincial Capital
The following is the schedule for Shadowless Day or the second main culmination in each provincial capital based on BMKG data:
Banda Aceh: 8 September 2026 at 12.36.30 WIB
Medan: 14 September 2026 at 12.20.56 WIB
Padang: 25 September 2026 at 12.10.20 WIB
Pekanbaru: 21 September 2026 at 12.07.23 WIB
Bengkulu: 3 October 2026 at 12.00.05 WIB
Jambi: 27 September 2026 at 11.56.39 WIB
Tanjung Pinang: 20 September 2026 at 11.55.46 WIB
Palembang: 30 September 2026 at 11.51.02 WIB
Bandar Lampung: 7 October 2026 at 11.46.52 WIB
Pangkal Pinang: 28 September 2026 at 11.46.18 WIB
Serang: 9 October 2026 at 11.42.44 WIB
Central Jakarta: 9 October 2026 at 11.40.02 WIB
Bandung: 11 October 2026 at 11.36.24 WIB
Semarang: 11 October 2026 at 11.25.02 WIB
Yogyakarta: 13 October 2026 at 11.24.51 WIB
Surabaya: 12 October 2026 at 11.15.43 WIB
Pontianak: 23 September 2026 at 11.35.08 WIB
Palangka Raya: 29 September 2026 at 11.14.52 WIB
Banjarbaru: 2 October 2026 at 12.10.09 WITA
Samarinda: 24 September 2026 at 13.03.40 WITA
Tanjungselor: 15 September 2026 at 12.05.53 WITA
Denpasar: 15 October 2026 at 12.05.00 WITA
Mataram: 15 October 2026 at 12.01.27 WITA
Kupang: 20 October 2026 at 11.30.33 WITA
Mamuju: 30 September 2026 at 11.54.33 WITA
Makassar: 6 October 2026 at 11.50.32 WITA
Palu: 25 September 2026 at 11.52.23 WITA
Kendari: 3 October 2026 at 11.39.04 WITA
Gorontalo: 21 September 2026 at 11.40.58 WITA
Manado: 19 September 2026 at 11.34.33 WITA
Sofifi: 21 September 2026 at 12.22.58 WIT
Ambon: 2 October 2026 at 12.16.45 WIT
Manokwari: 25 September 2026 at 11.55.31 WIT
Jayapura: 29 September 2026 at 11.27.39 WIT
Sorong: 25 September 2026 at 12.06.41 WIT
Nabire: 2 October 2026 at 11.47.29 WIT
Wamena: 3 October 2026 at 11.33.23 WIT
Merauke: 15 October 2026 at 11.24.16 WIT
The time differences are influenced by the geographical position of each area relative to the Sun. Members of the public who wish to observe this phenomenon can note the schedule according to their respective locations. Also ensure that the sky is clear enough so that changes in the object’s shadow can be seen clearly.