Chittagong (Chattogram), Bangladesh's second-largest city and main seaport, sits on the southeast coast on the Bay of Bengal, near the mouth of the Karnaphuli River and backed by low hills, at approximately 22.36°N, 91.78°E. It has a tropical monsoon climate (Köppen Am) — hot and humid year-round — with a hot dry season, a hot humid monsoon, and a short mild winter, and its coastal position leaves it squarely exposed to the cyclones of the Bay of Bengal.

The hot pre-monsoon season, from March to May, brings highs around 32–33°C and rising humidity, with violent pre-monsoon thunderstorms. The southwest monsoon then dominates from June to September, bringing warm temperatures, oppressive humidity and torrential, near-constant rain — the heart of the wet season, when the coastal hills wring enormous totals from the moist sea air and flooding is common.

Winter, from December to February, is short, mild, dry and pleasant, with January the coolest month — highs around 26–27°C and comfortable nights near 14–16°C, with low humidity and plenty of sunshine. This dry, warm, comfortable stretch is by far the best time of year, a welcome break from the long humid heat that dominates the rest of the calendar.

Chittagong is very wet, receiving on the order of 2,800–2,900 mm of rain a year, the overwhelming majority delivered by the southwest monsoon between June and September, when June and July are the wettest and heavy downpours regularly cause flooding and landslides in the hilly city. The winter months are largely dry. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Tropical cyclones are the gravest hazard of Chittagong's climate: sitting on the low, funnel-shaped northeastern coast of the Bay of Bengal, it is highly exposed to storms that most often strike before and after the monsoon (April–May and October–November), bringing destructive winds, torrential rain and deadly storm surge — the region has suffered some of the worst cyclone disasters in history. The monsoon itself is the other overwhelming feature, drenching the city for four months a year.

To follow any single measurement in Chittagong 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.