Australian Weather

Today, 1:20AM UTC

With two weeks left of the 2026 Australia winter, springlike warmth will spread across large parts of the most heavily populated corner of the country. While the coastal fringe of eastern Australia won’t feel particularly warm until the latter half of the week due to persistent showers with onshore winds, cities like Melbourne and Adelaide will come close to 20°C on Tuesday – with above-average maximums every other day this week. Even Hobart will come close to 20°C this week, with a top of 19°C on the cards for Wednesday (average August maximum 13.2°C) while Canberra can expect tops of 17°C or 18°C from Wednesday right through until Sunday (average August maximum 14.4°C). Because of the combination of a mild airmass and cloud, minimum temperatures are also likely to be relatively warm for winter across a broad area of the country for most of this week. Strong high pressure: the first ingredient for warmth Image: Synoptic chart for Australia at 10 am (AEST) on Monday, August 17, 2026, showing the strong high pressure system centred over Tasmania. Source: Weatherzone. A strong high pressure system was centred over Tasmania on Monday morning. The mean sea level pressure near the high’s centre exceeded 1041 hPa (hectopascals) in parts of Tasmania during the mid-morning. The BoM states that “a typical high is around 1020 hPa or higher”. So when the mean sea level pressure is up in the 1040s, you’re looking at a very strong high. Indeed, it was only a month ago that Australia registered a new provisional record for the highest mean sea level pressure, with a reading of 1044.5 hPa at the small central Tasmanian town of Ouse. Today’s high pressure system is not far off that. How the strong high is fuelling the unseasonable warmth Just like the above-mentioned record high pressure system in July, today’s high is also located further south than is typical for this time of year. That means it’s blocking influxes of cold air from reaching Tasmania or the eastern mainland. The high is also helping to funnel mild maritime air onshore, as winds circulate anti-clockwise around it. Already, Melbourne and Adelaide are under the influence of northeasterly winds which will swing more northerly as the week progresses. And as any local knows, northerlies usually mean warmer-than-average temperatures in any season. While the high will drift east over the Tasman Sea during the week, it will deflect the cold front which is currently sweeping through SW Western Australia this Monday, pushing any significantly cold air well south of the continent’s southeast. Not a great week for the snowfields Last week we wrote that the Australian snow season had neared the one-metre mark in depth at higher elevations, but that warm weather this week would likely erode the snowpack. That warm spell is now upon us, with maximums expected to reach as high as 6°C on at least two days this week at Thredbo Top Station – Australia's highest weather station at an elevation of 1957 metres. If you’re reading this in northern Australia and six degrees seems like a cold maximum, remember that everything is relative in weather, and that the average August maximum for Thredbo Top Station is just 0.6°C. The good news is that the 2026 snow season still has scope for improvement, with early signs of a snowy system next week. As ever, check the latest forecasts, snow cams and much more on the Weatherzone snow page.

16 Aug 2026, 2:56AM UTC

A very strong high pressure system centred over Tasmania will impact southern and eastern Australia’s weather over the coming days. How strong is this high pressure system? Mean Sea Level Pressure (MSLP) has already reached 1039.3 hPa at Ouse, Tasmania on Sunday morning, and is forecast to peak at 1041 or 1042 hPa on Monday morning. MSLP refers to the atmospheric pressure adjusted for elevation and is commonly used by meteorologists to normalise air pressure to a single level (sea level in this case). This allows pressure systems to be compared and mapped across the planet on a synoptic chart. Image: Synoptic chart showing a powerful high pressure system centred over Tasmania on Monday, August 17, 2026. Source: Weatherzone. High pressure systems are regions of higher MSLP and are usually associated with calm and dry weather due to dry air from the upper atmosphere descending towards the surface at the centre of these systems. In contrast, low pressure systems are region of lower MSLP due to rising air. These areas of lower surface pressure are characterised by increased cloudiness, winds, rain and storms. 6 weeks ago, on Monday, July 6, 2026, the weather station at Ouse, Tasmania registered an MSLP of 1044.5 hPa, setting the highest MSLP on record in Australia. This beat the previous record of 1044.3 hPa set at Launceston on July 7, 1967. This Monday is expected to fall 2-3 hPa short of the record, however the impacts of this high pressure system will be similar in strength and magnitude across broad parts of southern and eastern Australia in the coming days. How will this strong high pressure system influence Australia’s weather? Areas more directly underneath the central parts of this high will experience generally clear and calm conditions. This has allowed temperatures to drop quite significantly on Sunday morning, including minimum temperatures of: 3.0°C at Hobart Ap 2.7°C at Launceston Ap -4.7°C at Liawenee, Tasmania 6.1°C at Melbourne Image: Minimum temperatures on Sunday, August 16, 2026 across southeastern Australia. Source: Weatherzone. With this high strengthening further, another chilly morning is expected on Monday morning. Clear skies and cold conditions also led to widespread areas of fog, and some frost patches, experienced on Sunday morning over Tasmania and Victoria. Further widespread fog and frosts are expected over the next few mornings. Image: Satellite imagery on Sunday, August 16, 2026 showing morning fog across parts of Tasmania and Victoria dissipating. Source: Weatherzone. For the East Coast, onshore winds and showers are being directed by this high pressure system extending over 3,000km north of the central high pressure into Far North Queensland. Rainfall accumulations of 15-30mm are expected across much of the coast between NSW’s South Coast and Queensland North Tropical Coast from now to Wednesday. As seen in Saturday’s Weatherzone Story, parts of NSW’s Northern Rivers have already received rainfall accumulations of 20-40mm. Image: forecast rainfall accumulations to 10pm AEST on Tuesday, August 18, 2026. Source: Weatherzone. A more direct impact from this dominant high is the weight of the air above Tasmania and southern Australia on both people and water. With the average global MSLP sitting around 1013 hPa, the extra 20-30 hPa meant there’s about 2-3% more air mass sitting above the region, equivalent to about 200-300 kilograms per square metre. This 15-30 kilograms (up to 100-150 kilograms if lying flat!) above the average human can help ease joint pain and clear sinuses, but can also cause minor headaches. In the oceans, the added pressure pushes sea level down by around 1 centimetre by each 1 hPa increase. The 20-30 centimetre drop will be most noticeable on the low tides this Sunday and Monday, possible making some river bar crossings a little more challenging for boaters, and possibly revealing some interesting sand bar formations on the coastal stretches. Image: Forecast tides for Hobart on Sunday and Monday, August 16-17, 2026 as seen on the Marine and Tides section of the Weatherzone App. Changes in pressure with the changing climate Climate change and the expansion of the tropical region is increasing the intensity and frequency of these dominant high pressure systems. Image: MSLP anomalies across the latest 30 years (1991-2020) compared to the 30 years prior (1961-1990) showing the intensification of high pressure over southern Australia during Autumn. Source: ClimateReanalyzer.org Intense solar heating in the tropics causes air to rise into the upper atmosphere. This air then moves polewards, cools and sinks over the mid latitudes, forming our high pressure systems over Australia, before moving back towards the equator, warming and closing this loop called the Hadley Cell. The warming climate is intensifying this circulation, causing the descending branch of the Hadley Cell into Australia’s latitudes to be stronger and further south. This trend is evident across southern Australia throughout the year, but is most pronounced during autumn and winter. Image: Mean intensity of winter high pressure (MSLP) over the past 75 years across southern Australia, with the linear trend (blue) showing the increase in intensity. Data Source: Bureau of Meteorology. While high pressure is known to bring more settled weather, more intense and frequent highs can also enhance weaker low pressure systems, driving broader areas of strong winds, more persistent heatwaves and subdue rainfall over key agricultural regions. Lows often only affect one or two states, in contrast, broad high pressure systems like the one currently centred over Tasmania have expansive reaches into the far north of Queensland and west across the Great Australian Bight, bringing widespread impacts to much of the country.