Climate outlook for May to August

Long-range forecast overview

• May rainfall is likely to be below median for most of Australia, shifting to close to equal chances of above or below median rainfall in June.
• May maximum and minimum temperatures are likely to be above median for much of Australia however below median minimum temperatures are likely for parts of the southern mainland.
• May to July maximum and minimum temperatures have an increased likelihood of being unusually warm for most of Australia.

Rainfall—Summary

Below median May rainfall likely for much of Australia

• Forecast rainfall for May is likely to very likely (60% to greater than 80% chance) to be below median for most of Australia.
• May is the beginning of the dry season in northern Australia, and rainfall is usually low through to the start of the wet season in October. The drier than median forecast may not be noticeable for much of northern Australia.
• Historically, most other areas have between 10 and 200 mm of rainfall during May.
• Most of Australia away from the north-east and east has an increased likelihood of unusually low rainfall for May. Unusually low rainfall is defined as the driest 20% of May periods from 1981 to 2018.

A drier May likely to be followed by more typical conditions to start winter

• During June, there is a shift to roughly equal chances of above or below median rainfall for most of the country. For scattered areas for the southern mainland, forecast rainfall is likely (60 to 80%) to be above median
• Rainfall averaged across the 3 months May to July is likely to be below median for parts of southern, eastern, and northern Australia, dominated by the below median rainfall forecast for May.
• Parts of the south-east Australia, WA, northern Tasmania and eastern Queensland have an increased likelihood of unusually low rainfall for May to July.
• May to July rainfall has about equal chances of being above or below median for western WA, the southern NT, most of SA, southern Queensland away from the east and parts of western NSW.

Temperature—Summary

Warmer May days likely to very likely for most of Australia

• For May, forecast maximum temperatures are likely to very likely (60% to greater than 80% chance) to be above median for most of Australia apart from areas of the north, and southern Victoria.
• Most of the southern two-thirds of Australia, excluding far south-eastern Australia has an increased likelihood of unusually high maximum temperatures. Unusually high maximum temperatures are defined as the warmest 20% of May days from 1981 to 2018.
• Minimum temperatures are likely to very likely (60% to greater than 80% chance) to be above median for western WA, the northern and eastern NT, most of Queensland, far southern Victoria and Tasmania.
• There is an increased likelihood of unusually high minimum temperatures for western and WA, and parts of northern Queensland and NT. Unusually high minimum temperatures are defined as the warmest 20% of May nights from 1981 to 2018.
• Below median minimum temperatures are likely (60 to 80% chance) for most of SA, south-eastern WA, north-western Victoria, and western and southern NSW. These regions also have an increased likelihood of unusually low minimum temperatures. Unusually low minimum temperatures are defined as the coolest 20% of May nights from 1981 to 2018.

Warmer May to July days and nights likely to very likely for much of Australia

• While the months are getting cooler, forecast maximum and minimum temperatures for the three months May to July are likely to very likely to be above median (greater than 80% chance) for most of Australia for this time of year.
• For May to July, much of Australia has an increased likelihood of unusually high maximum and minimum temperatures. Unusually high maximum and minimum temperatures are defined as the warmest 20% of May to July days and nights from 1981 to 2018.

Climate influences

The Bureau's climate model simulates the physics of atmospheric, oceanic, ice and land surface processes, and uses millions of observations from satellites as well as in-situ instrumentation on land and at sea. These simulations enable the model to account for the influence of climate change and natural climate factors like ENSO, IOD, the Madden–Julian Oscillation (MJO) and SAM in its long-range forecasts.

Monitoring of current climate influences is presented below for general information:

• Global sea surface temperatures (SSTs) have been the warmest on record for each month between April 2023 and March 2024, with April 2024 SSTs currently tracking warmer than April 2023. Notably, the Atlantic Ocean is showing exceptional and prolonged warmth in sea surface temperatures.
• The Indian Ocean Dipole (IOD) is currently neutral. The most recent value of the IOD index (+0.68 °C) is above the positive IOD threshold (+0.40 °C). This is its seventh week above the positive IOD threshold. Typically, a positive IOD event is considered underway once the IOD index is sustained above +0.40 °C for about 8 weeks. Along with signs in atmospheric indicators, the model outlooks also indicate a positive IOD event may be developing. If a positive IOD develops, it would be earlier in the calendar year than is typical historically.
• The El Niño Southern Oscillation (ENSO) is neutral. Climate models indicate ENSO will likely continue to be neutral until at least July 2024.
• Australia's climate has warmed by 1.50 ± 0.23°C between 1910 and 2023, leading to an increase in the frequency of extreme heat events. In recent decades, there has been a shift to drier conditions across the south-west and south-east in the cooler season (April to October), due to a combination of natural variability on decadal timescales and changes in large-scale atmospheric circulation caused by an increase in greenhouse gas emissions.