Tropical Climate Update

Fortnightly outlook and recent conditions

For the week ending 13 July, conditions were settled across most of northern Australia. Rainfall was confined to far northern and eastern Queensland. High pressure systems were the dominant feature, resulting in slightly warmer than average days and cooler than average nights due to clear skies and increased radiative cooling. Minimum temperatures were up to 6 °C cooler than average in western Queensland and the northern Kimberley in WA.

For the fortnight of 19 July to 1 August, maximum and minimum temperatures are likely to very likely to be above average for northern and eastern Queensland, northern and central NT and the Kimberley. Days are likely to be cooler than average for much of WA's Pilbara region. There are early indications of the formation of a northwest cloudband pattern later in the fortnight, with above average rainfall likely to very likely across the northern Kimberley, most of the NT and western and southern Queensland.

Most of northern Australia, except for parts of tropical north Queensland, receives less than 25 mm of rainfall on average during July.

Warmer than average sea surface temperatures across the northern Pacific

For the week ending 13 July, sea surface temperatures (SSTs) were between 1.2 °C and 4 °C above average for waters surrounding Japan and much of the northern Pacific between 30 and 50°N, with broad areas exceeding 4 °C above average. Waters have warmed rapidly since early June 2025.

Widespread flooding and heavy rainfall, with daily totals exceeding 100 mm were observed across Tokyo on 10 July. The rainfall was historic in its intensity over a short time period and led to widespread damage and disruption to roads and rail services. The risk of landslides and further flooding remains in low-lying areas. Warmer than average SSTs can provide additional energy to increase the intensity of short-lived, heavy rainfall events.

Despite warmer than average SSTs, tropical activity in the north-west Pacific (west of the International Date Line) has been slightly below average with 5 named tropical storms so far in 2025; the 1991–2020 average to 13 July is 5.4. However, much warmer than average SSTs can provide more energy to tropical systems such as tropical cyclones (called tropical storms or typhoons in the north-west Pacific), often causing rapid intensification of developing storms.

Madden–Julian Oscillation forecast to strengthen

The Madden-Julian Oscillation (MJO) is currently moderately strong and located in the Maritime Continent. Most surveyed international models forecast that the MJO will strengthen in the coming week in the Western Pacific before a moderate to strong pulse progresses into the Western Hemisphere in late July. The predicted strengthening of the MJO to moderate to strong intensity would be the strongest the MJO has been since January 2025.

When the MJO is in the Maritime Continent and Western Pacific during July, it has historically had a drying impact on north-eastern Queensland. More broadly, the MJO may be favourable for above-average tropical cyclone formation in the north-west Pacific Ocean in the coming fortnight.

Northern Rainfall Onset

The northern rainfall onset outlook provides probabilistic forecasts for the first significant rains after 1 September for the 2025–26 wet season. The northern rainfall onset for the 2025–26 season is likely to be later than normal for western parts of northern Australia, but earlier for much of the east. Fortnightly updates are available on the Bureau's Northern Rainfall Onset page.