Lagos, Nigeria's largest city, sits on the coast of the Gulf of Guinea in the southwest of the country, on a low-lying sprawl of islands, lagoons and mainland just 6 degrees north of the equator at approximately 6.52°N, 3.38°E. It has a tropical wet-and-dry climate (Köppen Aw) — hot and humid year-round — where the year is shaped not by temperature but by the alternation of a long rainy season and a dry season, driven by the West African monsoon.

There is no summer in the temperate sense: temperatures stay warm and fairly steady all year, and the hottest months actually come in the dry season, around February and March, with highs around 32–33°C. The main rainy season runs from around April to October, and paradoxically the wettest, cloudiest months of June and July are the coolest, with highs easing to around 28°C as heavy rain and dense cloud hold the heat down.

Nor is there a true winter, but the dry season from November to March is the most settled time, with warm, sunnier days and somewhat lower humidity. Its most distinctive feature is the Harmattan, a dry, dust-laden wind blowing off the Sahara that can reach Lagos mainly between December and February, hazing the sky and briefly relieving the coastal humidity, though it arrives here less often than in northern Nigeria.

Lagos is wet, receiving on the order of 1,500–1,700 mm of rain a year, delivered in two pulses: a main peak around June, the wettest month with roughly 300 mm, and a secondary peak in September and October. A notable feature is the 'little dry season', a dip in the rains in August, which briefly eases the downpours even as the sky stays cloudy. Heavy rain regularly causes flooding in the low-lying city. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Two features define Lagos's weather: the 'little dry season' of August, a curious mid-rainy-season lull that briefly interrupts the downpours, and the Harmattan of midwinter, when Saharan dust occasionally reaches the coast. The overriding characteristic, though, is persistent humidity and heat, made heavier still by the surrounding lagoons and the urban heat island of the vast metropolis, with the sea breeze offering the main relief.

To follow any single measurement in Lagos more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.