Cold Temperatures Blanket West Nusa Tenggara (NTB) Due to the Australian Monsoon, Here Are Advisories for Tourists

Mataram – Over the past several days, residents across West Nusa Tenggara (NTB) have experienced cold temperatures from night through early morning. This phenomenon is a direct result of active surges of the Australian Monsoon, which carries cold air masses into regions south of the equator.

Satria Topan Primadi, Head of the Zainuddin Abdul Madjid (ZAM) Meteorological Station, confirmed in an official statement in Mataram on Sunday (31/5/2026) that wind patterns over NTB have now entered the Australian Monsoon phase. "Wind movement across NTB has transitioned to the Australian Monsoon system, which brings dry air masses that enable this current weather pattern," he explained.

Australian Monsoon Mechanism
The Australian Monsoon blows east to west, travelling from the high-pressure Australian continent towards the low-pressure Asian landmass. This periodic wind shift typically activates and strengthens between June and September. As this monsoon flows northwards towards Asia, equatorial regions enter the dry season. This air current carries very low moisture content, which drastically reduces cloud formation and rainfall.

Temperature Data and Weather Forecast
Based on Himawari-9 satellite observations recorded 30 May 2026, average air temperature across the entire West Nusa Tenggara region measured 21 degrees Celsius. Foothill areas of Mount Rinjani and Mount Tambora recorded temperatures around 14 degrees Celsius, while summit zones of both mountains dropped as low as 8 degrees Celsius.

For 31 May 2026, BMKG forecasts air temperatures across West Nusa Tenggara will fall between 18 to 32 degrees Celsius. Over the period 31 May to 1 June 2026, atmospheric humidity is projected to range 50 to 98 percent, with east-southerly winds blowing at maximum 20 kilometres per hour.

Cloud Cover and Humidity Contributing Factors
Satria confirmed another driver of the cold temperatures is minimal cloud cover during daytime and late afternoon. Without overhead cloud cover, solar heat absorbed by the ground is released far more rapidly. "After dark, heat that the earth absorbed during daylight escapes back into the atmosphere extremely quickly via outgoing thermal radiation, with no cloud layer to block this process," he detailed.

Additionally, low atmospheric humidity means surface heat cannot be retained after sunset. This allows much colder air from upper atmospheric layers to sink down to ground level, a standard characteristic of dry season conditions.

"We advise the public to maintain physical stamina and wear appropriate warm clothing for night and early morning activities. This temperature drop is a normal, expected occurrence during peak dry season," Satria stated, as quoted by ANTARA.

Advice for Travellers
Visitors planning trips to NTB, especially high altitude zones around Rinjani and Tambora, are advised to prepare sufficient gear. Given the extreme low temperatures recorded at the mountain summits, all travellers should carry proper insulated clothing and adequate sleeping equipment.

The dry atmospheric conditions during this season also carry elevated dehydration risk. Visitors are recommended to maintain consistent fluid intake and use skin moisturiser for comfortable outdoor activity.