Granite Island Weather Forecast
- 14
- 22
Rain
- 13
- 22
Cloudy
- 13
- 20
Cloudy
- 12
- 21
Cloudy
- 13
- 20
Cloudy
- 12
- 23
Sunny
- 13
- 30
Sunny
Today 21 Dec Mount Lofty Ranges
Partly cloudy. High chance of rain, becoming less likely this afternoon. The chance of a thunderstorm early this morning. Winds westerly 15 to 25 km/h increasing to 25 to 40 km/h in the morning then turning southerly 25 to 35 km/h in the late afternoon. Daytime maximum temperatures in the low to mid 20s.
South Central Coastal Waters
- Wind
- East to southeasterly 15 to 20 knots turning south to southwesterly 15 to 25 knots in the late morning and afternoon.
- Seas
- 1 to 1.5 metres, increasing to 1 to 2 metres during the afternoon.
- 1st Swell
- Southwesterly around 1 metre, increasing to 1 to 2 metres by early evening.
- Weather
- Partly cloudy. 90% chance of rain.
- Weather Situation
- A broad trough of low pressure lingers over the east and northern parts of the State. A low pressure system lies south of the bight and moves east to combine with the trough early Sunday. The combined low pressure system and trough then moves east to clear SA by late Sunday. A high pressure ridge then extends over the west and south of the State behind the low pressure system during Sunday. The high pressure ridge extends across the entire State and Coastal Waters by late Sunday and persists from Monday to Thursday.
Granite Island Temperature Statistics View More
December Temperature
Encounter Bay (2km)
Lowest 3 December, 2025
6.9 °CAverage December
18.6 °CHighest 18 December, 2025
40.7 °C
Climate (2020–Present)
Encounter Bay (2km)
Average Low 2020–2025
10.4 °CAverage 2020–2025
15.1 °CAverage High 2020–2025
20.6 °C