Monthly weather forecast and climate

Flag of Brunei
Flag of Brunei

The climate of Brunei

Brunei has a mainly tropical rainforest type of climate (Köppen climate classification Af). The climate is hot and humid, with ample rainfall for much of the year. At high altitudes, the climate is humid subtropical, with heavy rainfall. Brunei occupies hardly 1% of the northern coast of Borneo, an island in Southeast Asia. The East Malaysian state of Sarawak surrounds and divides Brunei into two parts. Brunei has a coastline of 165 miles with the South China Sea on its northern coast. The location in the equatorial tropics and the Southeast Asian wind systems govern the climate. The equatorial location gives Brunei an equal duration of days and nights throughout the year.

Brunei is a small country with a total area of 2226 square miles, just 4°N of the equator. Much of the terrain near the coast is a flat plain. Mountains rise in the east, and low hills comprise a large section of the west. The Borneo rainforests cover much of the inland regions of Brunei. Belait is the longest river with a length of only 20 miles. Bukit Pagon is the highest point in Brunei at 1850 meters. Brunei lies in the Inter-Tropical Convergence Zone near the equator, where the air masses from the northern and southern hemispheres meet. The southwest monsoon arrives during the period from June to September. The northeast monsoon is active from December to March. The orographic effect is prominent and brings 3657.6mm (144") to 4064mm (160") of rainfall in the mountains. Heavy rainfall occurs in short periods. Thunderstorms peak from April to May and September to November.

Brunei has two main seasons separated by two transitional periods. The dry season from February to April is scorching and receives relatively low rainfall. The wet season from October to January is hot and humid and receives abundant rainfall. Summers are severely hot and register a moderate amount of rainfall. March to September is usually hot, with high solar heating and a decrease in cloudiness and rainfall. The average high temperatures reach a peak of 32.8°C (91°F) in May, with many days above 37.8°C (100°F). Temperatures are usually in the hot range of 24°C (75.2°F) to 36°C (96.8°F) in the dry season. Winters are warm and sunny but bring plenty of rain. The temperatures in the wet season usually range between 20°C (68°F) to 28°C (82.4°F). The average low temperatures drop to 22.8°C (73°F) in January, with few days below 21.1°C (70°F). The skies remain overcast for much of the year. Brunei lies in the doldrums, where the northeast and southeast trade winds meet to create calm weather amid low wind speeds.

Brunei receives abundant average annual rainfall between 2921mm (115") and 3048mm (120"). The wettest period from October to January brings more than 1270mm (50") of precipitation, with the maximum rainfall in December. A second maximum occurs from May to mid-June. The first minimum occurs during the driest period from February to April, which receives at least 508mm (20") of rain. Late June to August experiences the second minimum. Brunei sees 205 rainy days in the year. The annual sunshine is more than 2550 hours, and the average daily sunshine lasts between 6.3 hours and 8 hours. The sunshine is intense, with the ultraviolet index at the peak of 12 much throughout the year. The average relative humidity remains above 85% and creates an uncomfortably high heat index. The average seawater temperatures are in the warm range of 26.7°C (80.1°F) to 30°C (86°F), which are suitable for swimming throughout the year. The average daily wind speeds are in the mild range of 7.4km/h (4.6mph) to 11.7km/h (7.3mph). December to March is the windiest part of the year in Brunei.

The record for the highest temperature in Brunei is 39.4°C (102.9°F). The lowest temperature on record is 14.4°C (57.9°F).

The best time to visit Brunei

The best time to visit Brunei is from January to March when the rain is relatively low, and the temperatures are bearable. February and March are dry, sunny, and the least wet months of the year. Visitors are fewer during the early part of the year, and there is plenty of space on the beaches. The humidity is relatively less than the summer, and the conditions are favorable for outdoor activities. Cold air masses from Siberia occasionally penetrate Brunei's shores during the northeast monsoon to bring low minimum temperatures.

The worst time to visit Brunei

The worst time to visit Brunei is during the extremely hot period between June and August. The rainfall is relatively less, but the heat is oppressive, and the humidity increases the heat index to high levels. The extreme heat makes people flee to the mountains rather than the lowlands of Banda Seri Begawan. The rainforests see plenty of visitors but are very humid in the summer months. The sticky weather makes the conditions challenging for people from cold countries.

Weather hazards

Brunei experiences weather hazards, such as floods, droughts, typhoons, and earthquakes. Tropical cyclones are frequent in the western Pacific during the southwest monsoon season. The storms originate in the equatorial and tropical waters and generally travel northwest to pass over the South China Sea to the north of Brunei. Squalls form over the Brunei waters as the strong southwesterly winds pass over them during tropical cyclones. The gusty winds significantly swell the waters and make the seas rough for navigation. Thunderstorms and heavy rainfall often accompany the squalls, but wind speeds rarely rise above 64.4km/h (40mph). Burning of slash and forest fires in the nearby islands of Indonesia are troublesome during the haze season from September to November. Brunei lies in the Pacific Ring of Fire, but mostly encounters earthquakes of mild intensity.

Weather in January

January is the coldest month of the year in Brunei, with average temperatures in the warm range of 22.8°C (73°F) to 30°C (86°F). Bandar Seri Begawan, the capital, registers average temperatures between 23.3°C (73.9°F) to 30°C (86°F), with overcast skies 83% of the time. Weather in January »

Weather in February

February is dry and sunny in the winter of Brunei, with less than 7 hours of daily sunshine. The sunlight is intense even in the winter, with the sunrise approximately at 6.30 a.m. and sunset at 6.30 p.m. Temperatures in Seria are usually are in the comfortable zone of 22.8°C (73°F) to 31.7°C (89.1°F). Weather in February »

Weather in March

March is the driest month of the year in Brunei, moderate rainfall between 101.6mm (4") and 127mm (5"). The average temperatures are in the warm 24.4°C (75.9°F) to hot 31.7°C (89.1°F) range, with at least 7.3 hours of daily sunshine. Weather in March »

Weather in April

April is hot and sunny in much of Brunei, with moderate precipitation in the range of 127mm (5") to 177.8mm (7"). The average temperatures are in the hot zone of 24.4°C (75.9°F) to 32.2°C (90°F), with clear skies for only 18% of the time. Weather in April »

Weather in May

May is the hottest month of the year in Brunei, with 7.5 hours of blistering sunshine during the long days. The average temperatures rise swiftly in the hot zone of 24.4°C (75.9°F) to 32.2°C (90°F). The sweltering heat often registers temperatures above 37.8°C (100°F), especially in the low-lying interior areas. Bandar Seri Begawan is cloudy for 88% of the time. Weather in May »

Weather in June

June lies in the hot summer season of Brunei, with intense sunshine and moderate rainfall. The southwest monsoon arrives in the country with full strength. The cloud cover sees a slight decrease from 85% to 80% of the time over the month. Weather in June »

Weather in July

July is hot and humid in Brunei, with no sign of respite from the oppressive heat. The only places of relief are the hilly areas above 1000 meters and the mild seawaters at 30°C (86°F). July has the lowest average low temperature of the year at 22.8°C (73°F). Weather in July »

Weather in August

August is hot and relatively dry in Brunei, with plenty of sunshine. The scorching sun keeps the daily highs between 29.4°C (84.9°F) to 31.7°C (89.1°F). Nights register average temperatures in the warm range of 22.8°C (73°F) to 25.6°C (78.1°F). Weather in August »

Weather in September

September is a transitional period reminiscent of the summer season in Brunei. The average temperatures are in the range of 23.3°C (73.9°F) to 31.7°C (89.1°F), with 6.5 hours of daily sunshine. Temperatures and humidity are high but comfortably lower than the peak summer. Weather in September »

Weather in October

October begins the wet season in Brunei, with ample rainfall and generally humid conditions. The precipitation is to the tune of 254mm (10") to 304.8mm (12"), with at least 21 wet days in the month. Tourists need to wear raincoats or carry umbrellas, with the possibility of a wet day at least 67% of the time. The average temperatures are in the 23.9°C (75°F) to 31.1°C (88°F) zone, and the nights are mild and humid in the wet season. Weather in October »

Weather in November

November brings abundant rainfall in Brunei during the northeast monsoon. Heavy rains lash the coast of Brunei and register at least 355.6mm (14") in the month. Thunderstorms are frequent from afternoon to midnight, but most of the precipitation is in the form of rain showers. The average temperatures hover in the 23.9°C (75°F) to 31.1°C (88°F) zone, with overcast skies up to 91% of the time. Weather in November »

Weather in December

December is the wettest month of the year in Brunei with 355.6mm (14") to 406.4mm (16") of heavy rainfall. The arrival of the winter season does not bring a substantial drop in temperatures. Winter days are often warm and humid, with at least a 63% chance of rain. Bandar Seri Begawan registers average temperatures in the 23.9°C (75°F) to 30.6°C (87.1°F) range, with only 6.5 hours of daily sunshine. Weather in December »