Wollongong experiences an oceanic climate (Köppen classification Cfb), closely bordering on a humid subtropical climate due to its warmest month averaging just under 22°C (71.4°F). This moderate coastal climate brings generally mild summers and cool winters. The city’s highest recorded temperature soared to 44.1°C on January 1, 2006, while the coldest temperature dipped to 0.8°C on July 27, 1986. On average, Wollongong enjoys around 107 clear days annually, balancing sunshine with its coastal weather patterns.

Rainfall is distributed throughout the year but tends to be heavier during the first half. The city’s unique geography plays a key role in its precipitation, with moist easterly winds from the Tasman Sea meeting the Illawarra Escarpment to create orographic lift — a process that encourages cloud formation and rainfall. This effect was dramatically evident on August 18, 1998, when Wollongong experienced a severe flood event, receiving 316 mm of rain in just three hours, while nearby Mt Ousley recorded over 445 mm. During the warmer months, thunderstorms occasionally bring intense lightning, heavy downpours, and even hail.

July and August are notable for strong westerly gales, often gusting over 100 km/h. These winds are dry foehn winds originating from the Great Dividing Range and occur mainly in winter and spring, especially on the leeward side of the escarpment. These gusty winds add to Wollongong’s dynamic climate, making the city’s weather both varied and distinctive.

Overall, Wollongong’s climate blends coastal moderation with occasional extremes, shaped by its proximity to the sea and the surrounding mountainous terrain.