Port Moresby, the capital of Papua New Guinea, sits on the southern coast of the island of New Guinea on the Gulf of Papua, at approximately -9.44°S, 147.18°E. Uniquely for the region, it lies in a rain shadow, giving it a tropical savanna climate (Köppen Aw) — hot and humid but surprisingly dry — with a distinct wet and dry season.

The wet season, from December to April — the austral summer — is hot and humid, with highs around 31–32°C and warm, sticky nights, when the northwest monsoon brings heavy afternoon downpours and thunderstorms. This is when nearly all of the year's rain falls, and the surrounding hills turn briefly green.

The dry season, from May to November — the austral winter — is warm, dry and breezy, with highs around 29–30°C and comfortable nights, as the southeast trade winds blow parallel to the coast rather than onshore. Rain is scarce for months, the surrounding hills turn brown, and this drier stretch is comfortably the more comfortable time of year.

Port Moresby is remarkably dry for New Guinea, receiving only around 1,000–1,200 mm of rain a year — while parts of the island receive over 4,000 mm — because the southeast trades blow parallel to its coast and the mountains behind it block the moisture. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Port Moresby is a striking anomaly: it sits on one of the wettest islands on earth, yet receives less than a third of the rain that falls on the highlands just inland, because the prevailing trade winds run parallel to its coast rather than onto it, leaving the capital's hills parched and brown for much of the year.

To follow any single measurement in Port Moresby 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.