Rosny Weather Forecast & Warnings (7018)

Climate and Coastal Influence

Rosny occupies a unique position on the eastern side of the Derwent River. Its weather is characterized by a temperate maritime climate, typical of southern Tasmania. Because it sits within the rain shadow of Mount Wellington (Kunanyi) to the west, Rosny often receives slightly less rainfall than the Hobart CBD. The river acts as a thermal regulator, often keeping overnight temperatures a fraction milder than inland Tasmanian towns during the winter months.

Seasonal Patterns and Wind

Spring and summer in Rosny frequently feature the famous sea breeze, known locally as the sea breeze coming up the Derwent. This can lead to rapid temperature drops in the mid-afternoon. During autumn and winter, the region is heavily influenced by cold frontal systems arriving from the Southern Ocean. These systems bring the majority of the annual rainfall and can result in significant wind gusts across the open reaches of the river.

Severe Weather and Regional Risks

While Rosny enjoys a relatively stable climate, it is susceptible to the vigorous westerly winds that track across the Great Australian Bight. Strong gale force winds can impact the Eastern Shore, particularly during late winter and spring. Residents should also be aware of the risk of frost during clear, still winter nights. Although less prone to extreme heat than mainland Australia, occasional northerly winds during summer can bring elevated fire danger periods across the grassy hills of the South East region.