Karachi, Pakistan's largest city and main port, sits on the Arabian Sea coast in the south of the country, on a low, arid plain at the edge of the Sindh desert at approximately 24.86°N, 67.00°E. It has a hot desert climate (Köppen BWh) strongly moderated by the sea — hot but not as extreme as the interior — with very little rain, high humidity and reliable sea breezes that make its coastal position central to its weather.

Summer is long and hot, with the pre-monsoon peak around May and June — highs around 34–35°C — made to feel far hotter by intense coastal humidity, so the 'feels-like' temperature can be oppressive. The sea breeze provides vital relief and keeps Karachi cooler than the scorching interior of Sindh; when that breeze fails during a heatwave, the results can be deadly, as in the catastrophic heatwave of June 2015. A weak, tail-end monsoon brings some rain from July to September.

Winter, from December to February, is mild, dry and pleasant, with January the coolest month — average highs around 25–26°C and comfortable nights near 10–13°C. Humidity drops, skies are clear and sunny, and the warm days and cool nights make this comfortably the best time of year. Genuine cold is unknown on this subtropical coast.

Karachi is very dry, receiving only around 150–200 mm of rain a year, most of it from the tail end of the summer monsoon between July and September, though totals are erratic and unreliable. When heavy monsoon rain or a rare Arabian Sea cyclone does strike, the low-lying city's limited drainage can lead to serious urban flooding, as in the record rains of August 2020. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

The defining feature of Karachi's weather is the sea: the Arabian Sea breeze moderates its heat and makes the coast far more bearable than inland Sindh, but also loads the summer air with the humidity that makes its heat dangerous. The city sits at the edge of the zone reached by Arabian Sea tropical cyclones, which most often threaten before and after the monsoon and can bring destructive wind and flooding rain.

To follow any single measurement in Karachi 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.