Climate and monthly weather forecast
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 3658mm (144.02") to 4064mm (160") of rainfall in the mountains. Heavy rainfall occurs in short periods. Thunderstorms peak from April to May and September to November.

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 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.

Brunei doesn't experience a typical spring due to its equatorial location. However, March to May sees the end of the northeast monsoon and the onset of hotter temperatures. During this transition, Brunei undergoes a slight decrease in cloudiness and rainfall. Average high temperatures soar, reaching their peak at 32.8°C (91°F) in May. Thunderstorms become more frequent, especially in April and May, contributing to the year's second maximum rainfall.

June to August is Brunei's summer, characterized by intense heat and elevated humidity levels. Temperatures frequently soar, with days often exceeding 37.8°C (100°F). Despite this, rainfall is relatively minimal during these months. The intense ultraviolet index, which remains at a peak of 12, makes it imperative for visitors to exercise caution when outdoors. Brunei's sea waters are inviting, maintaining temperatures between 26.7°C (80.1°F) to 30°C (86°F), ideal for swimming.

September to November in Brunei can be likened to the autumn of temperate regions. This period marks the onset of the wet season, with the environment remaining hot and humid. Rainfall becomes more frequent, particularly in October, which is among the wettest months. Thunderstorm activity is also at its peak during these months. Even though it's the onset of the wet season, the temperatures remain warm, ranging from 20°C (68°F) to 28°C (82.4°F).

Brunei's "winter" from December to February is more of a wet season than a cold one. The northeast monsoon ensures that these months receive substantial rainfall, with December registering the highest precipitation. Despite being the wet season, temperatures are warm, and the skies frequently remain overcast. The average low temperatures can dip to 22.8°C (73°F) in January, but days below 21.1°C (70°F) are rare. The wind speeds are also at their highest during this period, especially from December to March.

January is situated firmly within Brunei's wet season. Consequently, the month witnesses elevated levels of precipitation. In fact, January stands out as one of the months with the most substantial rainfall, only slightly behind December in terms of precipitation volume. Weather in January »

February ushers in a subtle shift in Brunei's climate. As the month progresses, the influence of the northeast monsoon begins to wane, leading to a gradual decrease in precipitation. Consequently, while January is marked by high rainfall, February sees a significant reduction, making it one of the drier months of the year. Temperature-wise, February continues the trend of warm days, with temperatures typically oscillating between 24°C (75.2°F) to 36°C (96.8°F). Weather in February »

March marks a notable transition in Brunei's climatic narrative, positioning itself as a clear departure from the wetter conditions of the preceding months. With the northeast monsoon's influence diminishing, rainfall sees a further decline compared to February, emphasizing the onset of drier conditions. Temperature levels in March undergo a noticeable elevation. Weather in March »

April firmly establishes itself in the dry season spectrum of Brunei's climate. As the remnants of the northeast monsoon's influence fade, the month is characterized by a substantial reduction in precipitation, with the volume of rainfall being markedly lower than the early months of the year. Temperatures during April consistently exhibit a warm profile. Weather in April »

May stands as a pinnacle of Brunei's dry season, reinforcing the patterns set by April but with added intensity. This month further cements its position in the dry spell, showing a continuing decrease in precipitation. Rainfall, though sparse, is often manifested in short, intense bursts, particularly in the form of peak thunderstorms which characterize this period. Temperature-wise, May is unyielding in its warmth. Weather in May »

June in Brunei marks the beginning of a significant meteorological shift. While the dry season's essence remains, there's a nuanced transition as the southwest monsoon begins to exert its influence. This heralds the approach of the wetter part of the year, though June itself still retains much of the dry season's character. In terms of temperature, June exhibits a pattern consistent with the preceding months, oscillating between 24°C (75.2°F) and 36°C (96.8°F). Weather in June »

July is a definitive marker of transition in Brunei's climatic landscape. The southwest monsoon's influence becomes more pronounced, pushing the country further into the embrace of the wet season. As the month progresses, Brunei starts experiencing the rhythmic interplay of increased rainfall and persistent warmth. Temperature readings in July are comparable to those of June, generally fluctuating between 24°C (75.2°F) and 36°C (96.8°F). Weather in July »

August in Brunei further immerses the country into the monsoonal embrace, blending the warmth of previous months with an increase in rainfall. The grip of the southwest monsoon tightens, reshaping Brunei's climate and echoing the profound shifts typical of the Southeast Asian region during this period. The temperatures in August hold steady, lingering between 24°C (75.2°F) and 36°C (96.8°F). Weather in August »

September stands as a climatic culmination in Brunei, with the southwest monsoon exerting its full force. The consistent rainfall of August evolves further, making this month one of the wettest in the nation's calendar. The elements come together to craft a symphony of rain, wind, and persistent warmth, painting a vivid portrait of Brunei's tropical rainforest climate. The temperatures during September remain in the familiar range of 24°C (75.2°F) to 36°C (96.8°F). Weather in September »

October in Brunei is a month of intriguing transitions, acting as a threshold between the concluding southwest monsoon and the impending onset of the northeast monsoon. The interplay of these significant wind systems dictates the climate during this period, rendering October both dynamic and unpredictable. The temperature range remains relatively stable, oscillating between 24°C (75.2°F) and 36°C (96.8°F). Weather in October »

November in Brunei ushers in subtle yet significant shifts in the climatic scheme, primarily owing to the rising influence of the northeast monsoon. With the southwest monsoon now a receding memory, the nation aligns itself with the climatic patterns steered by the approaching winds from the northeast. Temperatures, consistent with the preceding months, hover between 24°C (75.2°F) and 36°C (96.8°F). Weather in November »

December in Brunei is a distinctive month, characterised predominantly by the peak influence of the northeast monsoon. This period witnesses the merging of multiple climatic facets - consistent rainfall, temperate winds from the northeast, and relatively stable temperatures. The mercury continues its customary dance between 24°C (75.2°F) and 36°C (96.8°F), not deviating substantially from the patterns observed in preceding months. Weather in December »