Australian Weather

30 Jun 2026, 9:38AM UTC

Eastern Australia is seeing widespread rain and Australia’s ski resorts are struggling without natural snow as a rare atmospheric event unfolds in the Southern Hemisphere. The Southern Annular Mode (SAM) has entered an exceptionally strong positive phase over the past week, with the SAM index crossing +5.0 for the first time in three years. This rare atmospheric event is having a noticeable impact on Australia's weather. What is the Southern Annular Mode? The SAM is an index that reflects changes in the strength and position of a westerly wind belt encircling Antarctica. When the westerly wind belt strengthens and contracts south towards Antarctica, the SAM is in a positive phase, and when the westerlies slacken and expand further north towards Australia, the SAM is in a negative phase. The state of the SAM influences weather in Australia by affecting pressure patterns in the Australian region. For example, when a positive SAM occurs in winter, the cold fronts and low pressure systems that typically bring rain and snow to southern Australia move further south, and high pressure becomes more prominent near eastern Australia. These changes typically cause below average rain and snow in southern Australia and above average rain in parts of eastern Australia. Image: Typical impacts of a positive SAM event. Source: Weatherzone. Strong positive SAM underway Sustained SAM index values above +1 represent a positive SAM event, while sustained values below -1 reflect a negative SAM event. Late last week, the SAM index reached +5.06 on Friday, June 26. This exceptionally strong positive SAM value was the highest since May 2023 and one of the highest SAM values in modern records. The ongoing positive SAM is having a clear influence on Australia’s weather: Two rain bands are delivering widespread rain to Australia’s eastern and southeast inland this week. This wet weather is due in part to moisture-laden easterly winds flowing over eastern Australia, which is associated with a positive SAM. The Australian alpine region is also being starved of early-winter snow due to the ongoing positive SAM. Australia’s ski resorts are currently relying on artificially made snow in the absence of any decent natural falls. What will the SAM do in July? The SAM is difficult to predict more than a few days ahead. However, most computer model guidance suggests that the positive SAM will weaken in the first half of July. If this does happen, it will increase the likelihood of rain and snow in southern Australia heading in the coming weeks. There are already signs that a bout of fresh snow will fall in the Alps later this week, between late Thursday and Saturday. It is important to point out that the SAM is not the only climate index that influences Australia's weather, and other factors will play a role this winter. Most notably, the Bureau of Meteorology recently declared that El Niño is underway in the Pacific Ocean, which typically brings reduced rainfall and warmer-than-average daytime temperatures to much of Australia. The interaction between El Niño and the SAM will be key factor shaping Australia’s weather in the coming months.

30 Jun 2026, 1:06AM UTC

A vast rainband crossing eastern Australia has delivered widespread heavy rain, heaviest in northern and central Victoria, with Bendigo receiving 49.2 mm, its wettest June day since 1898. The rainband stretches all the way from Queensland to Tasmania. Other rainfall totals of note from this system in the 24 hours to 9 am Tuesday included: VIC 67.2 mm at  Specimen Hill Reservoir on Bendigo’s western outskirts, the highest reading in Victoria (and indeed anywhere in Australia). Falls between 50 mm and 60 mm recorded at five other locations across northern and central parts of the state. NSW 42.2 mm at Boullia, a sheep station in the state’s far northwestern corner – an unusual location for the highest NSW daily rainfall total in any season. 29 mm at Wamberra Station in the far southwest of the state, illustrating how this system has brought widespread rainfall across western NSW. QLD 38 mm at Nockatunga, a cattle station in far southwest Qld. Falls of more than 25 mm at no fewer than 10 other locations in the state’s southwest and far west. SA Numerous handy falls in the 10-20 mm range in eastern SA, from the North East Pastoral forecast district all the way down to the Lower South East TAS Falls between about 25 mm and 45 mm at multiple locations in Tasmania’s northwest. Why such heavy rain overnight? Image: Enhanced atmospheric water vapour satellite loop for the eight hours to 9 am (AEST) on Tuesday, June 30, 2026. Source Weatherzone. This is a system with tropical origins, as a moisture-laden air feed pours southwards, fuelled by warm waters off northern and eastern Australia. While heavy rain has fallen across a wide area and some places might feel chilly due to cloud cover and the short midwinter days, the airmass itself is relatively mild for June – although that will change by Friday as a strong cold front whips across the southeast. Rain continues during Tuesday with mild temperatures on the east coast Image: Combined radar and satellite image for Australia at 11 am (AEST) on Tuesday, June 30, 2026, showing the rainband crossing NSW, Vic and Tas. Source: Weatherzone. Rain will continue this Tuesday as the main rainband tracks eastwards. It will tend to run out of steam to an extent as it crosses the Great Dividing Range, delivering generally lighter falls to the east coast than to inland areas. Particularly heavy falls can be expected in the alpine region later this Tuesday, with totals in the 50 to 100 mm range possible. Mild temperatures are on the forecast for the east coast due to the northerly aspect of winds associated with this system. For example, Sydney is expected to kick off July with maximums of 22°C on Wednesday and 23°C on Thursday. The average July maximum (in what is statistically the city’s coldest month) is 16.5°C.