RRI.CO.ID, Jakarta - The Meteorology, Climatology and Geophysics Agency (BMKG), has forecast that most parts of Indonesia will continue to be dominated by low to moderate rainfall at the end of May 2026. The forecast applies to the third ten-day period of May 2026, from May 21 to 31. During this period, rainfall is generally expected to range between 0 and 150 millimeters per ten days.

In its latest climate outlook released on Monday, May 25, 2026, the Agency stated easterly winds have begun to become active toward the end of May. In addition, wind shear is also expected to occur around the equatorial region, influencing weather dynamics across Indonesia.

It also explained that atmospheric conditions in the previous ten-day period were still affected by atmospheric wave activity and global climate phenomena. One of them was the Madden-Julian Oscillation (MJO), which had previously been active in phase 2 over the Indian Ocean and phase 4 over the Maritime Continent.

The MJO activity is forecast to become active again until the end of the third ten-day period of May 2026, particularly in phase 6 over the Western Pacific. This condition is one of the factors shaping weather patterns in several parts of Indonesia.

Meanwhile, the NINO 3.4 index in the second ten-day period of May 2026 was recorded at 1.00. This value indicates warm conditions and has exceeded the neutral threshold for four consecutive ten-day periods.

BMKG estimates the probability of a weak El Nino at 100 percent, a moderate El Nino at 95 percent, and a strong El Nino at 60 percent. However, BMKG reminded the public that ENSO predictions in May 2026 are generally only accurate for the next three months, and therefore should be treated with caution.

In addition, the Indian Ocean Dipole (IOD), which is currently in a neutral condition, is forecast to potentially move toward a positive phase from July to November 2026. This change may affect rainfall patterns in several regions of Indonesia.

The areas expected to experience low rainfall, or less than 50 millimeters per ten days, include Aceh, parts of North Sumatra, Riau, Riau Islands, parts of West Sumatra, Jambi, Bengkulu, South Sumatra, and eastern Lampung.

Similar conditions are also forecast in northern West Java, parts of Central Java, East Java, Bali, Nusa Tenggara, parts of West Sulawesi, South Sulawesi, Gorontalo, Maluku, Papua, Central Papua, and South Papua.

Although low rainfall is expected to dominate, BMKG confirmed that no region in Indonesia is forecast to experience high rainfall or meteorological drought at the alert level during the period.

BMKG urged the public to continue monitoring the latest weather and climate information. This is important to anticipate the potential impacts of weather changes, especially on agriculture, disaster management, and water resource management.