Issued 9 December 2024

Introduction

With the rest of December still to come, this summary of Australia's climate and water data from 1 January to 30 November 2024 provides an early indication of Australia's annual mean temperature, rainfall and status of water resources for 2024.

Temperature

Overall, for January to November:

• The mean temperature was 1.42 °C above the 1961–1990 average, and the warmest on record since 1910.
• The mean maximum temperature was 1.44 °C above average, and the fourth-warmest on record since 1910.
• The mean minimum temperature was 1.39 °C above average, and the warmest on record since 1910.

The national mean, maximum and minimum temperatures for January to November were above average (warmest 30% of all years since 1910) for nearly all of Australia.

The warm conditions were widespread and persistent in 2024, with the mean national temperature for all months except April being above average. January to March and August to November were among the 10 warmest on record for their respective months. Consequently, summer 2023–24 was the third-warmest on record, winter the second-warmest and spring was the warmest on record.

Summer 2023–24 and spring both experienced frequent low-to-severe intensity heatwave conditions across large parts of the country, as slow moving high-pressure systems allowed heat to build up over much of the continent.

Conditions in autumn and winter were also dominated by frequent slow-moving high pressure systems to the south of the continent that brought about clear skies and light winds.

April was an exception to this pattern. A cold southerly airflow was directed over much of the continent, making it Australia's coolest April since 2015.

It was the warmest August on record nationally, with unprecedented heat across large parts of the country in the second half of the month. Many stations in Queensland, South Australia, Western Australia and Queensland recorded their warmest August and winter daytime temperatures on record.

Rainfall

The national January to November rainfall was 26% above the 1961–1990 average, the ninth-wettest January to November on record. However, the rainfall was not uniformly distributed across the country. January to November rainfall was above average for:

• the Northern Territory
• northern and inland parts of Western Australia
• most of Queensland
• northern and inland areas of New South Wales
• large parts of South Australia.

Rainfall was the highest on record (since 1900) for some parts of the central Northern Territory. January to November rainfall was below average for:

• coastal areas of south-west and north-west Western Australia
• southern parts of South Australia
• Victoria
• coastal areas of Tasmania
• an area of south-eastern New South Wales
• central areas of Queensland.

It was a wet start to 2024, with national rainfall for January and March among the 10 wettest on record for their respective months. In January, the monsoon and Tropical Cyclone Kirrily brought widespread rainfall across northern Australia. In southern, eastern and central parts of the country there were frequent outbreaks of thunderstorms.

The wet end to Australia's 2023–24 northern wet season contributed to above average rainfall over northern Australia (north of 26°S) and the fifth-wettest January to November on record and the highest since 2011.

Conditions across the country in autumn and winter were dominated by frequent slow-moving high pressure systems to the south of the continent that prevented rain bearing systems from reaching southern parts of the country. Cool season rainfall (April to October) across southern Australia was 10% below the 1961–1990 average.

During the northern dry season from May to September, there was unseasonal rainfall across parts of northern and central Australia. This was due to weather systems drawing in tropical moisture inland from surrounding warm oceans.

From August to November, thunderstorm activity associated with significant atmospheric moisture brought above average rainfall across large parts of Australia.

Water storages

Rainfall was very much below average in the south-western and south-eastern parts of Australia, where many water storages are located. As a result, catchments were dry and inflows to the water storages were low, causing water levels in these storages to decrease over the first 11 months of 2024. However, Australia's total surface water storage volume remained high and was at 71.8% of accessible capacity at the end of November.

The major storages in the Murray–Darling Basin have been in decline since late 2022. With dry catchment conditions and increased demand during the irrigation season (from October to March), total storage volume in the Murray–Darling Basin decreased from 85.6% at the start of the year to 73.7% at the end of November.

In northern Australia, very much above average rainfall resulted in high soil moisture and increased inflows to Lake Argyle, the largest water storage in Australia. In early April, Lake Argyle reached 159.0% of its accessible capacity, its highest since 2011. In the months that followed, Lake Argyle's volume steadily declined and was 95.4% by end of November.

At the end of November, surface water storages supplying capital cities were high (over 80.0% of their accessible capacity), except for Adelaide and Perth, at 49.2% and 47.5%, respectively. Both cities received below average rainfall during 2024.

Warragamba, the largest urban water supply storage in Australia, provides approximately 80% of the Sydney region's water supply. It started the year at 95.0% of its accessible capacity. In the first half of the year, the Warragamba dam spilled multiple times due to high inflows generated from above average rainfall across its catchments. The water level remained high for the rest of the year, reaching 97.5% of accessible capacity by end of November.

Wivenhoe, the largest storage in south-eastern Queensland, started the year at 62.6% of its accessible capacity and increased to 78.6% at the end of November, due to high inflows resulting from the above average rainfall and wet soil conditions at the beginning of the year.

Oceans

The year started with the 2023–24 El Niño returning to neutral conditions. Since April, sea surface temperatures (SSTs) in the central equatorial Pacific Ocean have been slightly cooler than the 1991–2020 average. However, the El Niño–Southern Oscillation (ENSO) has remained neutral (neither La Niña nor El Niño), with no consistent signal in ocean or atmospheric indicators of a La Niña developing.

The 2023–24 positive Indian Ocean Dipole (IOD) became inactive by late January 2024. From mid- October there were signs of a negative IOD developing. SSTs were generally warmer than average in the eastern tropical Indian Ocean, and close to average in the west (0.40 °C).

Record warm oceans globally were a key feature of 2024. From January to June, averaged over 60°S to 60°N, monthly SSTs were the warmest on record for their respective months. Global SSTs since July have been below the record temperatures observed during 2023, but above all other years since 1854.

Sea Ice

Antarctic sea ice (defined as the area of ocean where at least 15% of the surface is frozen) is an important component of the Earth's climate and ecology. It reflects incoming solar radiation, influences interactions between the ocean and atmosphere, contributes to the global ocean circulation, protects ice-shelves from ocean processes, and provides a habitat for polar species.

Similar to 2023, Antarctic sea-ice extent (a measure of the surface area of the ocean covered by sea ice) has been very much below average or close to record low values throughout 2024. During summer, when Antarctic sea ice is at its lowest, the extent dropped to 1.97 million km² on 18 February – the third lowest on record. During September, sea-ice extent reached its maximum of 17.2 million km², the second- lowest on record (behind 2023). These low values continue the much lower than normal values observed since 2016.

Global temperatures

In its provisional report on the State of the Global Climate in 2024 based on data for the first 9 months of 2024, the World Meteorological Organization (WMO) reported that the global mean surface temperature was 1.54 ±0.13 °C above the 1850–1900 average. 2024 is likely to be the warmest year on record for the globe, with the past 10 years (2015 to 2024) on track to be the 10 warmest on record.

Long-range forecast for December

The long-range forecast for December, issued on 28 November, indicated that maximum temperatures are likely to very likely (60% to greater than 80% chance) to be below average for eastern Western Australia, most of the Northern Territory and parts of inland Queensland, and likely to very likely (60% to greater than 80% chance) to be above average for western areas of Western Australia and parts of south-east Australia; elsewhere maximum temperatures are likely to be in the typical range for the season.

Minimum temperatures are very likely to be above average across Australia.

For December, rainfall is likely to be above average for most of Australia. This comes as northern Australia enters its wet season, after its fifth-wettest January to November on record.

Product code: IDCKGC7AR0