Nigeria spans latitudes 4°N to 14°N and experiences tropical climates differentiated primarily by distance from the Atlantic Ocean and elevation. The country divides into three broad climate zones: the coastal zone along the Gulf of Guinea receiving over 3000mm of annual rainfall, the middle belt receiving 1000mm to 1500mm, and the northern Sahel fringe receiving under 600mm annually. These zones do not correspond exactly to administrative boundaries but follow roughly parallel bands from south to north. The Niger River and Benue River systems create localized microclimates but do not fundamentally alter the latitude-driven rainfall gradient.
Nigeria recognizes two primary seasons rather than four: the wet season dominated by southwesterly monsoon winds from the Atlantic, and the dry season characterized by the Harmattan wind from the Sahara Desert. The timing and intensity of these seasons vary by latitude, creating distinct regional climate personalities that determine agricultural cycles, infrastructure strain, and traveler comfort. Temperature variation across the year remains relatively modest compared to temperate zones, with diurnal temperature swings often exceeding seasonal variation. Lagos maintains year-round temperatures between 25°C and 32°C, while Kano in the north experiences a broader range from 15°C on January mornings to 40°C in April afternoons.
The Harmattan is a northeast trade wind blowing from the Sahara Desert across West Africa, typically arriving in Nigeria between late November and mid-March. This wind carries fine dust particles that reduce visibility, sometimes to under 1000 meters at airports in Kano and Maiduguri. The phenomenon affects northern cities more intensely than coastal areas, though dust haze occasionally reaches Lagos in January. Airlines report Harmattan-related visibility delays at Murtala Muhammed International Airport in Lagos and Nnamdi Azikiwe International Airport in Abuja during peak Harmattan weeks in December and January. The dust deposits a reddish film on surfaces and dries mucous membranes, prompting increased sales of lip balm and eye drops in pharmacies throughout affected regions.
The Inter-Tropical Convergence Zone determines rainfall patterns across Nigeria by shifting north and south with the sun's seasonal position. This meteorological boundary between dry northern air masses and moisture-laden southern air masses reaches its northernmost position around August, bringing rain to cities like Sokoto and Maiduguri. By December, the ITCZ retreats south of Nigeria entirely, cutting off rainfall across the country except occasional storms in the extreme coastal margins. This northward and southward oscillation creates Nigeria's double maxima rainfall pattern in the south—two distinct rainy periods separated by a brief dry spell in August—while the north experiences a single continuous rainy season from May through September.
January marks the height of dry season along Nigeria's coast. Lagos records minimal rainfall averaging 15mm for the month across measurement stations at Murtala Muhammed Airport and Ikeja. Morning temperatures begin at 24°C, rising to 31°C by mid-afternoon. Humidity remains high at 75-80% despite the absence of rain, creating persistently muggy conditions that air conditioning mitigates but never eliminates. The Harmattan reaches Lagos weakly compared to northern cities, producing occasional hazy days rather than sustained dust storms. Port Harcourt in the Niger Delta receives slightly more rainfall than Lagos in January, approximately 25mm, as its position further east and south places it marginally closer to equatorial moisture sources. Calabar near the Cameroon border records similar totals. Beach conditions along the Gulf of Guinea remain favorable in January with moderate surf and water temperatures near 27°C. Hotels in Victoria Island and Ikoyi report peak occupancy as international business travelers and diaspora visitors time trips to avoid rainy months.
February continues dry season conditions with rainfall remaining under 30mm across Lagos, Port Harcourt, Calabar, and Warri. Temperatures climb marginally, with Lagos afternoon peaks reaching 32°C. The brief respite from rain allows road maintenance crews to repair damage from the previous wet season, particularly in Port Harcourt where flooding during rainy months renders some streets impassable. Harmattan influence begins diminishing in February as the ITCZ starts its gradual northward migration. Humidity remains oppressive, particularly in the Niger Delta cities of Port Harcourt and Warri where proximity to creeks and mangrove swamps maintains moisture levels above 80% even during dry season. Calabar experiences slightly cooler temperatures than Lagos due to its southeastern position and surrounding rainforest, with afternoon peaks around 30°C. The Cross River flowing through Calabar provides no cooling effect on city temperatures but contributes to local humidity.
March represents a transitional month when the ITCZ begins moving northward and rainfall increases sharply. Lagos receives approximately 100mm across the month, typically falling in intense afternoon thunderstorms rather than steady drizzle. These storms arrive with dramatic suddenness—clear skies at 2pm can become torrential downpours by 3pm, flooding low-lying areas in Lagos Mainland and parts of Lekki within 30 minutes. Port Harcourt's rainfall increases to 150mm in March, while Calabar receives closer to 180mm as its proximity to the Atlantic and Cameroon Highlands enhances orographic lifting. Temperatures peak in March before the rainy season's cloud cover provides slight relief. Lagos regularly records 33°C in March, making it one of the year's hottest months despite increasing rainfall. Warri in the western Niger Delta follows patterns similar to Port Harcourt with March rainfall around 140mm and afternoon temperatures reaching 32°C.
April brings the wet season in full force to coastal Nigeria. Lagos receives 150mm to 180mm depending on the year, with rain falling on approximately 12 days of the month. Individual storms can dump 50mm in two hours, overwhelming drainage systems constructed decades ago for a smaller population. Port Harcourt's April rainfall reaches 200mm, while Calabar receives 250mm as maritime air masses from the Gulf of Guinea collide with the Cameroon Highlands to the east. Temperatures moderate slightly under increased cloud cover, with Lagos afternoons around 31°C rather than March's 33°C. Humidity climbs above 85% in all coastal cities, creating conditions where clothing never fully dries without mechanical assistance. Mold becomes a persistent problem in buildings lacking climate control. The Niger Delta cities of Port Harcourt, Warri, and surrounding communities experience the beginning of seasonal flooding that will intensify through subsequent months. Creeks overflow and low-lying residential areas see water entering ground floors.
May represents peak rainfall for Lagos, averaging 250mm across the month. Storms intensify in duration and frequency, with rain falling on 15 to 18 days. The city's inadequate drainage causes widespread flooding in areas including Festac Town, parts of Surulere, and informal settlements in Ajegunle. Traffic congestion, already severe, becomes catastrophic during afternoon storms as flooding closes roads and motorists abandon stalled vehicles. Port Harcourt receives 300mm in May while Calabar measures 350mm, making it one of the wettest major cities in West Africa. The Cross River swells significantly, though severe flooding events typically require rainfall sustained over multiple months. Temperatures remain stable around 29°C to 31°C with minimal diurnal variation due to cloud cover. Warri in the Delta records approximately 320mm in May. All coastal cities report humidity levels persistently above 85%, creating ideal conditions for mosquito breeding despite government fumigation campaigns.
June continues heavy rainfall across coastal Nigeria though totals decline slightly from May's peak. Lagos receives 200mm to 220mm, Port Harcourt around 280mm, and Calabar approximately 400mm. Calabar's June rainfall often exceeds May's total, making it the city's wettest month depending on yearly variation. The southwestern monsoon blows consistently from the Atlantic, bringing moisture-laden air that produces both intense convective storms and extended periods of steady rain. Lagos experiences less sunshine in June than any other month, with cloud cover reducing solar radiation and keeping afternoon temperatures around 29°C. The so-called "August break"—a brief reduction in rainfall between the two rainy season peaks—does not yet appear in June, which remains thoroughly wet. Road travel between cities becomes hazardous as potholes expand and unpaved sections turn to mud. Port Harcourt's limited road network means flooding on one major route can isolate entire neighborhoods. Calabar's topography provides slightly better drainage than the flat Niger Delta cities, though low-lying areas near the Cross River still experience water accumulation.
July rainfall totals decline modestly across coastal Nigeria, signaling the approach of the August break. Lagos receives 150mm to 180mm in July, concentrated in the first and last weeks of the month. Port Harcourt measures approximately 250mm while Calabar records 350mm, maintaining its position as Nigeria's wettest major city. The Harmattan remains absent, replaced entirely by humid Atlantic air. Temperatures hold steady at 28°C to 30°C with oppressive humidity above 85%. The sun appears more frequently than in June, though afternoon clouds and storms remain common. Warri experiences flooding comparable to Port Harcourt, with July totals around 240mm. The Niger Delta's complex creek system means flood waters drain slowly, sometimes persisting for days after individual storms. Agricultural communities along the coastal belt time planting cycles to the rainfall pattern, with yam and cassava cultivation depending on predictable wet season arrival.
August introduces the "August break"—a brief dry spell interrupting the rainy season in southern Nigeria. This phenomenon results from a temporary southward retreat of the ITCZ before its final northward push. Lagos receives only 80mm to 100mm in August, roughly half of July's total. Rainfall concentrates in fewer, more intense events rather than frequent light showers. Port Harcourt's August total drops to 150mm while Calabar receives 200mm, both representing significant declines from previous months. Temperatures increase marginally as cloud cover decreases, with Lagos afternoons reaching 30°C to 31°C. The break provides relief from constant dampness and allows infrastructure repairs that are impossible during peak rainfall months. However, humidity remains above 80% even without rain. Calabar's Cross River National Park receives less rainfall than the city itself due to topographic rain shadow effects, though 200mm still falls across the park area in August.
September marks the resumption of heavy rainfall after the August break. Lagos receives 180mm to 200mm as the ITCZ makes a final northward movement before beginning its seasonal retreat. Port Harcourt measures 280mm in September while Calabar records 380mm, returning to June-level totals. Flooding that had begun receding in August returns with September's rains. The Niger Delta experiences its most severe flooding in September and October as months of accumulated rainfall saturate the ground and swell rivers. Warri records approximately 300mm in September. Temperatures remain stable around 29°C due to cloud cover. The combination of rainfall and heat creates maximum humidity stress, with readings consistently above 85%. Mold growth accelerates on any surface not regularly cleaned. Calabar's humidity occasionally drops to 80% when rare easterly winds from drier interior regions temporarily interrupt the Atlantic monsoon, but such events last hours rather than days.
October maintains wet conditions across coastal Nigeria though rainfall begins declining as the ITCZ retreats southward. Lagos receives 150mm to 170mm in October, with the last intense storms of the rainy season often occurring in the month's first two weeks. Port Harcourt measures 250mm while Calabar records 320mm. Flooding persists through October in the Niger Delta as soils remain saturated and drainage systems operate at capacity. Warri experiences approximately 260mm of rainfall. Temperatures begin increasing as dry season approaches, with Lagos afternoons reaching 31°C by month's end. The transition from wet to dry season proceeds unevenly, with some Octobers remaining thoroughly wet while others show clearer drying trends. Calabar typically remains wetter longer than Lagos due to its southeastern position and proximity to equatorial moisture sources.
November brings the dry season's onset along Nigeria's coast. Lagos receives 60mm to 80mm, primarily in the first week of the month. Port Harcourt measures approximately 90mm while Calabar records 120mm, maintaining its status as the wettest coastal city even during dry months. Harmattan dust begins appearing in the atmosphere toward month's end, though the haze remains light compared to December and January. Temperatures climb as cloud cover dissipates, with Lagos afternoons reaching 32°C. Humidity declines from wet season peaks but remains above 75%. The Niger Delta's flood waters finally recede in November, exposing damage to homes and infrastructure that occurred during the rainy season. Calabar's rainfall in November concentrates in the first two weeks before tapering off sharply. The return of consistent sunshine makes November popular for domestic tourism, with Nigerians from drier inland cities traveling to beaches around Lagos and Calabar.
December completes the transition to full dry season conditions. Lagos receives less than 30mm of rainfall for the month, with some Decembers recording no measurable precipitation at stations across the city. Port Harcourt measures approximately 40mm while Calabar records 50mm, mostly falling in the first week. Harmattan influence increases, bringing occasional hazy days when visibility drops below 5 kilometers. The December-January period represents Lagos's peak tourist season, with hotels in Victoria Island, Ikoyi, and Lekki charging premium rates. Temperatures reach 32°C on most afternoons, while nights cool to 24°C. Humidity drops to 70-75%, providing modest relief from the 85%+ readings typical during rainy months. Calabar hosts its annual Christmas carnival in December, drawing visitors who benefit from dry weather and moderate temperatures around 30°C. Port Harcourt and Warri similarly experience dry conditions with minimal rainfall.
January brings full dry season conditions to Nigeria's middle belt. Abuja receives negligible rainfall, typically under 5mm for the entire month. The Harmattan blows consistently, reducing visibility at Nnamdi Azikiwe International Airport to 2000 meters on heavily dust-laden days. Morning temperatures in Abuja drop to 17°C, climbing to 33°C by afternoon, creating a 16°C diurnal range far exceeding coastal variations. Jos, situated on the Jos Plateau at 1200 meters elevation, experiences cooler conditions with morning temperatures around 12°C and afternoon peaks near 28°C. The elevation makes Jos the coldest major Nigerian city, with January representing the chilliest month. Kaduna in the northwest receives under 3mm of rain in January with Harmattan dust reducing visibility more severely than in Abuja. Enugu in the southeast remains marginally wetter than other middle belt cities, receiving approximately 15mm in January due to its position closer to moisture sources. Makurdi on the Benue River records minimal rainfall under 5mm.
February continues bone-dry conditions across the middle belt. Abuja receives less than 5mm of rainfall with Harmattan dust remaining prominent. Afternoon temperatures climb to 35°C while mornings start at 18°C. The combination of heat and dust creates challenging conditions for outdoor activities. Jos maintains cooler temperatures with mornings around 13°C and afternoons reaching 29°C, making it Nigeria's most temperate major city. The plateau's elevation creates conditions that feel almost Mediterranean during dry season, though the landscape remains thoroughly African savanna. Kaduna experiences intense Harmattan effects in February, with dust storms occasionally reducing visibility to under 1000 meters. Temperatures range from 16°C at dawn to 36°C by mid-afternoon. Enugu receives approximately 20mm in February, marking it as the wettest middle belt city during dry season. Makurdi records under 10mm with morning temperatures around 18°C rising to 34°C.
March marks the beginning of climatic transition in the middle belt. Abuja's rainfall increases to approximately 30mm, typically falling in a few isolated storms rather than regular events. Temperatures peak in March before the rainy season's cloud cover provides relief, with afternoon readings reaching 36°C. Morning temperatures rise to 22°C as the Harmattan diminishes and southerly air masses begin penetrating northward. Jos receives around 40mm in March with afternoon temperatures climbing to 30°C, warm by plateau standards. Kaduna measures approximately 20mm of rainfall with temperatures ranging from 20°C to 37°C, making March one of the hottest months before the rainy season arrives. Enugu transitions more quickly toward wet season with March rainfall reaching 60mm, double February's total. Makurdi receives approximately 50mm in March as thunderstorms begin appearing in late afternoon.
April brings the rainy season to Nigeria's middle belt, though totals remain modest compared to coastal cities. Abuja receives 100mm to 120mm across the month, falling primarily in afternoon thunderstorms that develop over the city's hills. Temperatures moderate slightly under increased cloud cover, with afternoons around 34°C rather than March's 36°C. Jos measures 130mm in April, with the plateau's elevation enhancing convective storm development. Afternoon temperatures on the Jos Plateau reach 29°C while mornings remain cool at 17°C. Kaduna's April rainfall totals approximately 80mm with temperatures ranging from 21°C to 35°C. Enugu receives 150mm in April as its southeastern position places it under maritime influence earlier than cities further north and west. Makurdi on the Benue River records 120mm with afternoon temperatures around 33°C.