Brunei Darussalam is entering the Northeast Monsoon in early December 2023 and is expected to persist until around end of March 2024.

The first two months of Northeast Monsoon (December 2023 and January 2024), also known as the rainy season, are the months that normally receive the highest amount of rainfall and have recorded the highest number of rain days, in comparison to the other months. During this period, the country normally experiences unsettled weather conditions with occasional heavy showers or thundershowers especially during the night until early morning.

Based on climatological data, December recorded an average rainfall of 358.9 mm, and an average rainfall of 320.6 mm for January. The average number of rain days for December and January are 21 days and 18 days, respectively.

During the rainy season, it is important for the general public to take note of the high risk of flooding or flash floods especially at low-lying and flood prone areas as well as near the river banks. The risk of severe flooding may occur during the event of heavy rain coinciding with high tide and as well as the occurrence of landslide and falling trees during continuous heavy rain that lasts for more than 1 hour.

Strong cold surges from Northeast may also result in the increase of wave height over Brunei waters to rough state that
may reach up to 3.5 meters and wind speed may increase up to 50 km/h. Rough sea conditions would be dangerous to all small crafts, and sea recreational activities and sports (such as swimming, jet skiing and scuba diving) during this season.

Whereas, during the second half of Northeast Monsoon (February and March 2024), the atmospheric conditions tend to be more stable with lesser rainfall activities, with average rainfall for February of 162.9 mm and 143.4 mm for March. Meanwhile, the average number of rain days for February and Mac are 12 days and 13 days, respectively.

However, with the El Niño conditions which are currently observed over our region, Brunei Darussalam is expected to experience suppressed rainfall activity and rainfall amount with increased air temperature.

Hotter and drier weather conditions are likely to happen during the peak of the El Niño event around early 2024, especially in February and March 2024, which are the two driest months for Brunei Darussalam, in comparison to the other months. Maximum daily temperatures may reach up to 34.0°C or more during the afternoon. Excessive Hot Weather (EHW) or commonly known as heatwave event in Brunei Darussalam
also tends to occur during El Niño episodes.

Based on international climate models, this El Niño episode is expected to continue until June 2024.

Therefore, the seasonal outlook for the rainfall amount for the period of December 2023 until February 2024 is as follows:


December 2023
-Normal (280-430 mm)

January 2024
-Slightly Below Normal (190-260 mm)

February 2024
-Below Normal (≤100 mm)

In light of this, members of the public are advised to take precautionary actions and appropriate measures in dealing with the impacts that relate to the active weather condition forecasted during this rainy season, as well as, during the drier weather condition forecasted in February and March 2024. Public, road users and mariners are advised to always be up to date with the latest weather forecast, advisory and warning issued by Brunei Darussalam Meteorological Department, and to make any necessary planning to ensure
safety.

We shall continue to monitor the weather conditions and will issue weather advisories or warnings if necessary. Latest weather information, advisories and warnings can be accessed easily through our mobile app, Brunei WX, as these weather information, advisories and warnings can be received immediately after they are issued. Latest weather information can also be obtained by contacting the duty meteorological forecaster at our Forecast Centre, through our Weather Line 114, by visiting our website at www.met.gov.bn or follow our Facebook (@bruneiweather) and Instagram (@bruneiweather).

Wallahu a’lam Bissawab.