Brazil occupies 8,515,767 square kilometers across latitudes 5°N to 33°S, producing five distinct climate zones governed by the equatorial convergence, Atlantic maritime influence, and interior continental effects. The country experiences two primary seasonal patterns: equatorial regions near Manaus and Belém maintain consistently high temperatures year-round with defined wet and dry periods, while subtropical areas from São Paulo through Porto Alegre experience four distinct seasons with winter temperatures occasionally approaching freezing. The Atlantic coastal strip from Natal to Rio de Janeiro operates on a tropical monsoon pattern, the interior Cerrado and Pantanal follow savanna rainfall cycles, and the semi-arid Caatinga of the northeast interior receives irregular precipitation averaging 200-800 millimeters annually.
The Amazon basin including Manaus and Belém records daily rainfall totaling 250-300 millimeters during January, the peak of the wet season running November through May. Manaus registers average daily highs of 30-31°C with overnight lows near 23°C, while relative humidity reaches 85-90 percent. The Negro River at Manaus typically rises one to two meters during January as upstream precipitation accumulates. Belém receives slightly more rainfall at 320-380 millimeters with temperatures matching Manaus within one degree. Afternoon thunderstorms arrive with regularity between 14:00 and 17:00, producing brief intense downpours followed by clearing skies.
Salvador and the Bahia coast experience their warmest and wettest period during January with 100-130 millimeters of precipitation spread across 12-15 rain days. Daytime temperatures reach 29-30°C with ocean temperatures at 27°C. Recife and Natal share similar conditions with 80-120 millimeters of rainfall and temperatures 28-30°C. The Atlantic surf runs higher during January with swells reaching 1.5-2.5 meters along northeastern beaches. Fortaleza marks the tail end of its dry season with minimal rainfall below 30 millimeters and daily temperatures 29-31°C.
Rio de Janeiro and the southeastern coast endure peak summer heat during January with afternoon temperatures frequently reaching 35-38°C in the city center, though ocean breezes moderate coastal neighborhoods to 30-32°C. Monthly rainfall totals 110-140 millimeters concentrated in brief intense storms, often occurring overnight. The Cristo Redentor station at 710 meters elevation records temperatures 4-6 degrees cooler than sea level. São Paulo experiences similar heat with afternoon highs 28-31°C and monthly rainfall 220-280 millimeters, heaviest in late afternoon. The Serra do Mar generates orographic lifting that produces localized flooding when storm systems stall against the escarpment.
The Pantanal wetlands in Mato Grosso do Sul reach maximum inundation during January as the Paraguay River and tributaries crest from upstream rainfall. Water levels at Corumbá rise to 4-5 meters above dry season baselines, flooding 80-90 percent of the region's 150,000 square kilometers. Daily temperatures reach 32-35°C with humidity above 80 percent. Thunderstorms deliver 180-220 millimeters monthly. The southern Pampas region around Porto Alegre records 100-120 millimeters with temperatures 25-29°C and occasional subtropical storm systems bringing 50-80 millimeter rain events over 24-48 hours.
Brasília experiences peak wet season conditions during January with 240-280 millimeters of rainfall across 18-22 days. Afternoon thunderstorms develop with remarkable consistency, typically initiating between 15:00 and 17:00 as daytime heating triggers convection over the Planalto Central plateau at 1,000-1,200 meters elevation. Temperatures range 18-28°C. The Cerrado vegetation reaches maximum greenness as the 1,200-1,800 millimeter annual rainfall concentrates between October and April. Curitiba at 25°S latitude records 140-170 millimeters during January with temperatures 17-26°C, marking the warmest month in this subtropical highland city at 930 meters elevation.
Fernando de Noronha records minimal rainfall during January with totals below 40 millimeters as the archipelago 350 kilometers offshore experiences different meteorological influences than the mainland coast. Daily temperatures hold steady at 28-30°C with ocean temperatures 27-28°C. Underwater visibility reaches 30-40 meters during this period. Lençóis Maranhenses on the Maranhão coast begins accumulating the seasonal rainfall that fills interdune lagoons, receiving 120-160 millimeters during January with temperatures 29-31°C.
Manaus and the central Amazon continue peak wet season through February with 230-270 millimeters of rainfall distributed across 18-20 days. River levels continue rising, with the Negro River typically reaching its annual maximum stage in June, three to four months after peak rainfall due to drainage lag from the vast basin. Temperatures remain constant at 30-31°C daily highs and 23-24°C overnight. Belém receives 330-400 millimeters during February, the rainiest month of the year, with afternoon storms intensifying as the Intertropical Convergence Zone positions directly overhead. The Amazon River discharge at Óbidos reaches approximately 180,000 cubic meters per second during this period, though peak discharge occurs later in May-June.
Salvador rainfall decreases slightly from January to 90-110 millimeters during February while temperatures hold at 29-30°C. The city's upper districts 100-150 meters above sea level receive 20-30 percent more rainfall than coastal neighborhoods due to orographic enhancement. Recife and Olinda experience continuation of the rainy season with 140-180 millimeters concentrated in intense morning storms. Natal records 100-140 millimeters with temperatures unchanged from January at 28-30°C. Ocean currents shift slightly warmer as the South Equatorial Current strengthens, bringing water temperatures to 27-28°C along the northeastern coast.
Rio de Janeiro maintains summer heat through February with daily highs 30-33°C, though rainfall diminishes to 80-110 millimeters from January levels. Copacabana and Ipanema beaches record ocean temperatures at their annual maximum of 25-26°C. The city experiences an average of 8-10 days with measurable precipitation during February. São Paulo receives 200-240 millimeters with temperatures 28-31°C and relative humidity 75-85 percent during afternoon hours. The Tietê and Pinheiros rivers flowing through São Paulo reach elevated levels during February, occasionally causing localized flooding in low-lying districts when daily rainfall exceeds 60-80 millimeters.
The Pantanal remains extensively flooded during February as water levels stabilize near seasonal maximums. Temperatures at Corumbá average 31-34°C with heat index values approaching 40°C when humidity exceeds 85 percent. Monthly rainfall totals 130-160 millimeters. Wildlife concentrates on elevated ground and tree platforms as shallow feeding areas become inaccessible. Porto Alegre and the southern coast record 110-130 millimeters during February with temperatures 24-28°C. Subtropical air masses occasionally penetrate northward, bringing multi-day rain events totaling 40-70 millimeters when frontal systems stall across Rio Grande do Sul.
Brasília continues wet season patterns with 200-240 millimeters spread across 16-19 rain days during February. The Paranoá Lake, a 48 square kilometer reservoir created during the city's construction in 1956-1960, reaches high water levels. Temperatures range 18-27°C. Curitiba receives 150-180 millimeters with daytime highs 25-28°C, though overnight temperatures occasionally drop to 16-18°C when southern cold fronts briefly reach this latitude. Florianópolis on the Santa Catarina coast records 140-180 millimeters with temperatures 23-29°C and ocean temperatures peaking at 24-25°C.
Fortaleza transitions into its primary rainy season during late February as the ITCZ moves southward, with monthly totals increasing to 80-120 millimeters from the negligible amounts recorded in December-January. Daytime temperatures hold at 29-31°C. The Ceará interior including areas around Juazeiro do Norte receives 100-150 millimeters during February, critical for the semi-arid Caatinga vegetation. Chapada Diamantina in inland Bahia receives 60-100 millimeters with temperatures 18-26°C at elevations reaching 1,200-1,700 meters, where the plateau topography moderates the intense heat experienced at lower elevations.
The Amazon basin begins transitioning toward reduced rainfall during March, though totals remain substantial at 220-260 millimeters in Manaus and 300-380 millimeters in Belém. River levels continue rising despite slightly reduced precipitation due to upstream runoff reaching main channels. Temperatures show no appreciable change from previous months at 30-31°C daily and 23°C overnight. The Amazon River at its mouth near Belém discharges freshwater 100-150 kilometers into the Atlantic, creating a visible plume of sediment-laden water distinct from the blue ocean. Relative humidity maintains 85-90 percent throughout the basin.
Recife and the Pernambuco coast experience peak rainfall during March with 240-320 millimeters concentrated in heavy morning downpours lasting 2-4 hours. The city's historic Olinda district, positioned on hills rising 100-120 meters above the coastal plain, receives 15-25 percent more precipitation than beach neighborhoods. Temperatures hold at 27-29°C. Natal records 180-240 millimeters during March, the wettest month, with similar morning-heavy rainfall patterns. Salvador begins transitioning toward drier conditions with 80-120 millimeters and temperatures 28-30°C. The São Francisco River, which drains 640,000 square kilometers across Brazil's interior before reaching the Atlantic between Alagoas and Sergipe, reaches elevated discharge during March from accumulated Cerrado and Caatinga rainfall.
Rio de Janeiro marks the end of summer with decreasing rainfall to 100-130 millimeters during March and slightly moderating temperatures to 27-31°C for daily highs. The city averages 10-12 rain days during March. Ocean temperatures begin their gradual decline from the 25-26°C February peak. São Paulo receives 150-190 millimeters with afternoon highs 26-29°C. Day length decreases from the December solstice maximum of approximately 13 hours 40 minutes to 12 hours 20 minutes by the March equinox at this 23°S latitude. The Atlantic Forest surrounding both cities receives substantially higher rainfall than urban areas, with Serra do Mar slopes recording 200-350 millimeters depending on elevation and exposure.
The Pantanal begins its gradual drainage during March as rainfall decreases to 130-180 millimeters and regional rivers crest. The Paraguay River at Corumbá typically reaches maximum stage during late March or early April before beginning a six-month recession lasting into September-October. Water temperatures reach 28-30°C in shallow flooded areas. Porto Alegre records 100-140 millimeters during March with temperatures 22-27°C as autumn arrives in this southern subtropical location. Occasional cold fronts from Patagonia reach Rio Grande do Sul during March, bringing sharp temperature drops of 10-15 degrees over 24-hour periods.
Brasília continues active wet season through March with 180-240 millimeters and temperatures 18-27°C. The city experiences an average of 17-20 days with measurable rainfall during March. Afternoon thunderstorm development follows consistent patterns with cloud formation beginning around 13:00 and precipitation commencing 15:00-17:00. Goiânia, 200 kilometers southwest of Brasília at 750 meters elevation, records similar totals of 200-250 millimeters with temperatures 19-29°C. Curitiba receives 130-170 millimeters as subtropical autumn progresses, with temperatures 17-25°C and increasing frequency of overcast days.
Fortaleza and the Ceará coast experience peak rainfall during March with 240-340 millimeters, representing 20-25 percent of the annual total concentrated in this single month. The coastal city records temperatures 27-30°C with high humidity 80-90 percent. Interior Caatinga regions receive 100-180 millimeters, their primary annual moisture. São Luís in Maranhão records 300-380 millimeters during March with temperatures 25-30°C as the city experiences the heart of its wet season. Lençóis Maranhenses receives 200-280 millimeters during March, accumulating in the interdune lagoons that form the distinctive landscape feature appearing between March and September.
Manaus records 220-280 millimeters during April as the wet season continues through its penultimate month before the sharp May transition. The Negro River continues rising toward its typical June maximum despite slightly reduced local rainfall, fed by drainage from the vast western Amazon tributaries including the Japurá and Içá rivers flowing from Colombia and Peru. Temperatures remain constant at 30-31°C with overnight lows 23-24°C. Belém receives 280-360 millimeters with similar temperature profiles. The Amazon River discharge increases to approximately 200,000 cubic meters per second at Óbidos as upstream precipitation continues concentrating through the drainage network. Forest canopy remains continuously wet throughout April with relative humidity holding above 85 percent.
Recife continues heavy rainfall through April with 250-340 millimeters spread across 16-20 rain days. Morning storms deliver 50-80 percent of daily precipitation between 05:00 and 10:00, followed by afternoon clearing. Temperatures moderate slightly to 26-28°C as the sun's declination shifts northward past the equinox. Natal records 240-300 millimeters during April, its second-wettest month after March. Fortaleza rainfall decreases sharply from the March peak to 160-240 millimeters as the ITCZ shifts northward. Salvador receives 100-150 millimeters with temperatures 26-28°C, beginning the transition toward the June-August dry season minimum.
Rio de Janeiro experiences substantial rainfall decrease during April to 70-100 millimeters as autumn establishes. Daily high temperatures drop to 26-29°C with overnight lows reaching 20-22°C. Ocean temperatures decline to 24-25°C. The city records 8-10 rain days during April. São Paulo receives 70-90 millimeters, the driest month of the year, with temperatures 15-25°C showing increased daily range as continental air masses replace humid maritime influence. Overnight temperatures in São Paulo occasionally reach 12-14°C during cold front passages in late April. The Tietê River flow decreases substantially from the January-March wet season peaks.
The Pantanal water recession accelerates during April as rainfall drops to 80-120 millimeters and the Paraguay River begins falling from its March-April crest. Water levels at Corumbá drop 20-40 centimeters during April, initiating the gradual exposure of flooded grasslands. Temperatures remain warm at 28-32°C though humidity decreases slightly from wet season peaks. Wildlife begins concentrating along permanent water channels as temporary pools drain. Porto Alegre records 90-120 millimeters during April with temperatures 18-24°C. Frost occasionally occurs in inland Rio Grande do Sul areas above 600-800 meters elevation during strong polar outbreaks in late April.
Brasília marks the end of the primary wet season during April with rainfall decreasing to 120-180 millimeters from the January-March peak. Afternoon thunderstorm frequency diminishes to 12-16 days during the month. Temperatures range 17-27°C with increasing overnight cooling as dry continental air replaces the humid tropical masses dominating October-March. The Cerrado vegetation begins transitioning toward dormancy as available soil moisture declines. Curitiba receives 80-110 millimeters with temperatures 14-22°C, experiencing the clear autumn weather characteristic of Brazil's southern highlands. Morning fog develops with increasing frequency in the Paraná valleys surrounding Curitiba as overnight radiative cooling intensifies under clearer skies.
Fortaleza continues substantial rainfall through April with 160-240 millimeters, though totals decline from the March maximum. The northeastern coast begins its transition toward the June-November dry season. Temperatures hold at 27-30°C with ocean temperatures 27-28°C. João Pessoa in Paraíba records 200-280 millimeters during April, maintaining the wet pattern extending through May for this portion of the coast. Belo Horizonte at 850 meters elevation in Minas Gerais receives 50-80 millimeters with temperatures 16-27°C as the city enters its dry season. The São Francisco River maintains elevated discharge during April from the accumulated Cerrado runoff, though levels begin declining from February-March peaks.