Penang (George Town), a historic island city in northwestern Malaysia, sits in the Strait of Malacca off the west coast of the peninsula, backed by forested hills at approximately 5.41°N, 100.34°E. Just a few degrees north of the equator, it has a tropical rainforest climate (Köppen Af) — hot, humid and rainy year-round with no true dry season.

There is no summer in the temperate sense: temperatures barely change, with daytime highs around 32–33°C and warm, humid nights near 24–25°C every month, and humidity consistently high. The typical rhythm is a hot, bright morning building into towering afternoon thunderstorms, with sea breezes off the strait offering some relief on the coast.

Nor is there a true winter, but the relatively drier stretch comes from around December to February, during the northeast monsoon, when the peninsula's western side is sheltered and rainfall eases. The wettest months are typically April–May and September–October, at the monsoon transitions, when thunderstorms are most frequent and intense.

Penang is wet, receiving on the order of 2,400–2,700 mm of rain a year, with rain in every month and no true dry season, though the heaviest falls come in the inter-monsoon periods around April–May and September–October. Heavy downpours regularly cause flash flooding and landslides on the island's steep hills. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Penang's rainfall peaks at the monsoon transitions rather than during the monsoons themselves, and the island's steep, forested hills make it prone to landslides during intense downpours. Sheltered on the strait, it escapes the direct force of the northeast monsoon that batters Malaysia's east coast each winter.

To follow any single measurement in Penang 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.