Bissau Climate & Monthly Temperature Overview – Guinea-Bissau

Dry Season: November to April

During the dry season, Bissau experiences warm and dry weather with temperatures ranging from 25°C (77°F) to 32°C (90°F). This is the best time to visit Bissau as there is minimal rainfall and the humidity is relatively low. Clear skies and sunshine are prevalent, providing ample opportunities for outdoor activities and sightseeing. However, the dry harmattan winds from the Sahara can sometimes make the air hazy.

Wet Season: May to October

In contrast to the dry season, the wet season in Bissau is characterized by heavy rainfall, high humidity, and occasional thunderstorms. Temperatures remain relatively warm, ranging from 26°C (79°F) to 30°C (86°F). However, the constant rainfall and high humidity can make the weather feel oppressive and uncomfortable at times. July and August are the peak rainy months, receiving the heaviest precipitation. During the wet season, it is advisable to pack waterproof gear and prepare for unpredictable weather conditions.

Average Temperature in Bissau

Bissau, the capital of Guinea-Bissau, experiences a tropical monsoon climate, characterized by high temperatures year-round. The average temperature in Bissau remains relatively constant throughout the year, with slight variations between the rainy and dry seasons. During the wet season, from May to October, the average temperature ranges between 26°C and 32°C (79°F and 89°F), with high humidity and frequent rainfall. In the dry season, from November to April, the average temperature drops slightly to a range of 22°C to 30°C (72°F to 86°F), with less humidity and occasional showers.

Overall, Bissau experiences warm to hot temperatures throughout the year, with the wet season being slightly warmer and more humid than the dry season. However, due to its coastal location, Bissau is subject to moderate sea breezes that provide some relief from the tropical heat, making the climate more comfortable, especially during the dry season.

Cloud Cover and Precipitation in Bissau

Bissau, the capital city of Guinea-Bissau, experiences a tropical climate with distinct wet and dry seasons. During the wet season, from May to October, the skies over Bissau are frequently covered in clouds, leading to high humidity and abundant precipitation. The average monthly rainfall during this period ranges from 100 to 300 millimeters, peaking in July and August. The cloud cover associated with the wet season brings relief from the intense heat and provides a much-needed source of moisture for the surrounding vegetation.

In contrast, during the dry season, from November to April, cloud cover over Bissau is significantly reduced, resulting in drier conditions and lower humidity. Although rainfall is still possible during this time, it is generally less frequent and less intense than during the wet season. The lack of cloud cover during the dry season allows for more direct sunlight, leading to higher temperatures and increased evaporation. The reduced precipitation and increased sunshine during the dry season can impact water availability and agricultural activities in the region.

Annual Precipitation

Bissau, the capital of Guinea-Bissau, experiences a significant amount of precipitation throughout the year. The city receives an average of 1,740 millimeters (68.5 inches) of rain annually. The wet season typically begins in May and lasts until October, with the months of July and August seeing the highest rainfall. During this period, heavy downpours and thunderstorms are common, resulting in temporary flooding in some areas.

Seasonal Variations

The dry season in Bissau spans from November to April. During this time, rainfall is much less frequent, averaging around 200 millimeters (8 inches) per month. However, even during the dry season, occasional showers may occur. The difference in precipitation between the wet and dry seasons is attributed to the influence of the intertropical convergence zone, a band of low pressure that brings moisture from the Atlantic Ocean. During the wet season, the ITCZ moves northward, bringing increased precipitation to Bissau.

Rainfall Seasonality and Patterns

Bissau, the capital of Guinea-Bissau, experiences a tropical monsoon climate with a pronounced wet season from May to October and a dry season from November to April. During the wet season, heavy rainfall is common, with the city receiving an average of 120 centimeters (47 inches) of precipitation over the six-month period. The heaviest rainfall occurs in August, with an average of 25 centimeters (10 inches) in that month alone. The dry season is characterized by minimal precipitation, with most months receiving less than 1 centimeter (0.4 inches) of rainfall.

Monthly and Annual Variation

The amount of rainfall can vary considerably from month to month and year to year. The wettest year on record was 1971, when Bissau received 201 centimeters (79 inches) of precipitation. In contrast, the driest year on record was 1984, when the city received only 49 centimeters (19 inches). The monthly rainfall distribution also varies, with some months experiencing more rainfall than others. For example, in 2020, Bissau received 29 centimeters (11 inches) of rainfall in June, while it received only 10 centimeters (4 inches) of rainfall in January.

Historical Occurrences and Challenges

Bissau, Guinea-Bissau, is situated close to the equator in West Africa, characterized by a tropical climate with consistent high temperatures throughout the year. Snowfall is an extremely rare phenomenon in this region due to the absence of atmospheric conditions conducive to snow formation. The last and only recorded instance of snowfall in Bissau occurred on December 21, 1972, during an unusually cold spell. The snowfall was brief and light, covering the ground with a thin layer of snow that quickly melted away.

Climate Factors and Climate Change

The lack of snowfall in Bissau can be attributed to several climate factors. The city experiences high temperatures year-round, with an average daily temperature ranging from 25 to 30 degrees Celsius (77 to 86 degrees Fahrenheit). Additionally, Bissau’s proximity to the equator means that the region receives abundant sunlight, further contributing to warm temperatures. The city also experiences high humidity, which inhibits the formation of snow. Climate change and rising global temperatures further exacerbate these conditions, making snowfall even less likely in Bissau and other equatorial regions.

Sunrise and Sunset Times:
The sun rises and sets relatively consistently throughout the year in Bissau, Guinea-Bissau, due to its proximity to the equator. The sunrise typically occurs around 6:30 AM, with minor variations throughout the year. Similarly, sunset generally takes place around 6:30 PM, providing approximately 12 hours of daylight. These consistent timings offer predictable sunlight hours for daily activities and weather patterns.

Sunshine Hours:
Bissau experiences abundant sunshine year-round, with an average of 8 to 9 hours of sunshine per day. The driest months, from November to April, typically have longer sunshine hours, reaching up to 10 hours per day. Even during the rainy season, from May to October, Bissau still receives a substantial amount of sunshine, with an average of 6 to 7 hours per day. This ample sunshine contributes to the warm and sunny climate that Bissau is known for.

Moon’s Phases in Bissau

The Moon’s phases are a regular occurrence that is influenced by the Moon’s orbit around Earth and its changing illumination from the Sun. In Bissau, Guinea-Bissau, the Moon’s phases follow a predictable pattern, with each phase lasting approximately 7 days. During the new moon phase, the Moon is not visible from Bissau as it lies between Earth and the Sun, causing its night side to face Earth. As the Moon orbits Earth, it gradually becomes illuminated by the Sun, resulting in the crescent moon, first quarter, waxing gibbous, and full moon phases. The full moon occurs when the Moon’s entire face is illuminated and lies opposite the Sun.

Moon’s Position

The Moon’s position in the sky can be observed from Bissau. The Moon rises in the east and sets in the west, following a daily cycle. Its altitude and azimuth constantly change throughout the night, and its movement is highly predictable. The Moon’s altitude, or the angle between the Moon and the horizon, can vary significantly, particularly during the new moon phase when the Moon is close to the horizon. Additionally, the Moon’s azimuth, or the horizontal angle between the Moon and true north, is used for navigation and orientation. The Moon’s position in the sky can be used to determine the time and direction in the absence of other reference points.

Seasonal Humidity Variation

Bissau, the capital of Guinea-Bissau, experiences significant seasonal variation in humidity throughout the year. The driest months are December through April, with average relative humidity levels ranging from 50% to 60%. During this period, the harmattan, a dry, dusty wind blowing from the Sahara Desert, reaches Bissau, bringing in low moisture content and suppressing humidity.

From May to November, the wet season brings increased humidity as moisture-laden winds from the Atlantic Ocean flow into Bissau. Average relative humidity levels soar to 80-90%, particularly during the peak rainy months of July and August. The high humidity levels can create a muggy and uncomfortable atmosphere, making outdoor activities less enjoyable.

Impact on Health and Infrastructure

The extreme humidity in Bissau during the wet season can have negative impacts on health. High humidity levels can aggravate respiratory conditions such as asthma and allergies, and it can also lead to heat exhaustion and dehydration. The humid environment also provides favorable conditions for the growth of mold and mildew, which can contribute to respiratory problems and damage buildings and infrastructure. It is essential to take precautions during periods of high humidity by staying hydrated, wearing breathable clothing, and maintaining proper ventilation in homes and offices.

Wind Speed

Bissau, the capital of Guinea-Bissau, experiences moderate to strong wind speeds throughout the year. During the dry season (November to April), winds are predominantly northeasterly and average between 10 to 20 knots (19-37 km/h). During the wet season (May to October), winds shift to a southwesterly direction and tend to be stronger, with average speeds ranging from 15 to 25 knots (28-46 km/h). These winds are influenced by the West African monsoon and often bring heavy rainfall.

Wind Patterns

The wind patterns in Bissau are closely tied to the seasonal changes in the region. The northeasterly winds during the dry season are part of the Harmattan, a dry, dusty wind that blows from the Sahara Desert. This wind can significantly reduce visibility and bring dust and sand into the city. The southwesterly winds during the wet season are associated with the monsoon and bring moisture from the Atlantic Ocean, resulting in increased precipitation. Bissau’s location on the Atlantic coast also exposes it to occasional tropical cyclones, which can bring high winds and heavy rain.

Optimal Season (November to April)

Bissau’s dry season, spanning from November to April, is the most favorable time to visit. During this period, rainfall is minimal, and the weather is generally sunny and hot, with average temperatures hovering around 27-32°C (81-90°F). The skies are clear, providing excellent visibility for exploring the city’s landmarks and attractions. Moreover, the dry season coincides with several cultural festivals and events, offering visitors an opportunity to immerse themselves in the local traditions and festivities.

Shoulder Season (May to October)

The shoulder months, from May to October, present a different experience in Bissau. This is the city’s rainy season, characterized by frequent showers and occasional thunderstorms. However, these showers usually occur in the evening or overnight, leaving ample time for daytime exploration. The average temperature during the rainy season is slightly lower at 23-29°C (73-84°F). The lush greenery and abundant birdlife during this time create a refreshing and serene atmosphere, perfect for nature enthusiasts and birdwatchers. Travelers may also enjoy discounts on accommodation and tours during the shoulder season, making it a budget-friendly time to visit Bissau.

Potential and Challenges

Bissau, the capital city of Guinea-Bissau, has significant potential for solar energy development. The country receives abundant sunshine year-round, with an average annual solar radiation of around 1,900 kilowatt-hours per square meter. However, the deployment of solar energy faces challenges such as high upfront costs, limited grid infrastructure, and a lack of technical expertise. Despite these challenges, the government has made efforts to promote solar energy through incentives and partnerships with international organizations.

Current Projects and Impacts

Several solar energy projects are currently underway in Bissau. One notable project involves the installation of a 1.2-megawatt solar photovoltaic (PV) system on the campus of the National University of Guinea-Bissau. The system provides clean and reliable electricity to the university, reducing its reliance on fossil fuels. Additionally, several small-scale solar PV systems have been installed in rural areas, providing access to electricity for communities that previously lacked it. The implementation of solar energy in Bissau has had positive impacts on economic development, education, and healthcare services.

Coastal Plains

Bissau, the capital city of Guinea-Bissau, lies along the Atlantic coast, characterized by extensive coastal plains. These plains are generally flat, with elevations ranging from sea level to around 100 meters. The plains are composed of alluvial deposits, brought down by rivers from the interior. The coastal plains are home to mangroves, salt flats, and other wetlands, which support a rich biodiversity.

Inland Plateau

Beyond the coastal plains, the topography of Bissau transitions into a gently undulating inland plateau. This plateau rises gradually towards the eastern border with Guinea, reaching elevations of up to 300 meters. The plateau is covered by savanna vegetation, dominated by grasses and scattered trees. The plateau is drained by several rivers, including the Mansoa River and the Corubal River, which flow westward towards the Atlantic Ocean. The plateau is also home to numerous granite outcrops, which form distinctive landmarks in the landscape.

Osvaldo Vieira International Airport

Osvaldo Vieira International Airport (OXB) is the primary airport serving Bissau, Guinea-Bissau. Situated approximately 11 kilometers northeast of the city center, it is the country’s main gateway for domestic and international air travel. The airport has a single asphalt runway measuring 2,250 meters and is capable of handling a range of aircraft types, including Boeing 737s and Airbus A320s. OXB features a modern terminal building with basic amenities such as customs, immigration, baggage claim, and a few shops. Additionally, there are currency exchange services and local transport options available for passengers. The airport is well-connected to Bissau via road networks, making it easily accessible for travelers.

OXB serves several domestic and regional destinations within West Africa, including Dakar, Abidjan, and Praia. International connections include Lisbon, Porto, and Madrid, among others. The airport is a hub for Binter CV, the regional subsidiary of Spanish airline Binter Canarias, which operates flights to various destinations in the neighboring islands and mainland Africa. Other airlines operating at OXB include TAP Air Portugal, Royal Air Maroc, and Air Senegal. With its strategic location and expanding connectivity, Osvaldo Vieira International Airport plays a vital role in the transportation and tourism sectors of Guinea-Bissau.

History and Culture

Bissau, the capital and largest city of Guinea-Bissau, has a rich and diverse history. Founded by the Portuguese in the 16th century as a slave trading post, it later became the administrative center of Portuguese Guinea. After Guinea-Bissau gained independence in 1973, Bissau became its capital. The city is a melting pot of cultures, reflecting its Portuguese colonial past and its African heritage. Bissau is home to the National Ethnographic Museum, which houses exhibits on the traditional cultures of Guinea-Bissau’s various ethnic groups. The city also has a vibrant arts scene, with numerous galleries and performance venues.

Geography and Climate

Bissau is located on the Geba River estuary, on the Atlantic coast of Guinea-Bissau. It is a low-lying city, with much of its area at or below sea level. The city’s climate is tropical, with a rainy season from June to October and a dry season from November to May. During the rainy season, Bissau experiences heavy rainfall and flooding. The city is also prone to erosion, which has led to the loss of land along the coast. Bissau’s population is estimated to be around 490,000, making it the most populous city in Guinea-Bissau.