Authors: Andy Casely Krystelle Ho Valentina Koschatzky
In this report, we provide a comprehensive overview of the key climate drivers and potential impacts on the region.
Key takeaways
- Negative Indian Ocean Dipole (IOD) event and wetter spring for Eastern Australia
A negative Indian Ocean Dipole event, which began in August, is expected to peak during September and October 2025. Historically, such events have been linked to wetter-than-average conditions across much of Australia, particularly in the eastern regions. This year’s negative IOD, combined with elevated sea surface temperatures, is driving forecasts for significant rainfall, increasing the likelihood of a wet spring season. - ENSO neutral conditions with a La Niña Leaning
The El Niño–Southern Oscillation (ENSO) remains neutral but is leaning slightly towards La Niña. Updated forecasting models from the Bureau of Meteorology (BoM) suggest neutral conditions will persist through spring, with a chance of La Niña developing by the end of the year. This marginal shift could further amplify rainfall patterns across Australasia. - Drought and bushfire risk eases in Southern Australia
Recent rainfall across drought-affected regions of South Australia and western Victoria has provided much-needed relief. While soil moisture levels remain shallow, the easing of drought conditions is expected to reduce bushfire risks in these areas during the upcoming season. - Flood risk elevated in Eastern Australia
Heavy rainfall in eastern Australia, combined with high antecedent soil moisture levels, has significantly increased the risk of flood events. The forecasted above-average rainfall across inland regions and coastal areas further heightens the potential for flooding during spring. - Warm and wet spring for New Zealand
New Zealand is forecast to experience a warm and wet spring, particularly in the North Island. La Niña-like weather patterns and easterly wind anomalies are expected to bring tropical moisture to the region, resulting in above-average rainfall. Elevated ocean temperatures are also contributing to warmer conditions across the country. - 2025: On track to be the third warmest year on record
The first half of 2025 has been exceptionally warm, ranking as the second hottest on record globally despite minimal influence from natural climate drivers like ENSO. This trend underscores the accelerating impact of human-induced global warming, with 2025 on track to become the third warmest year ever recorded.
These climate dynamics are shaping up to have widespread implications for agriculture, infrastructure, and risk management across Australasia. For a detailed analysis of the seasonal outlook and its potential impacts, read the full report.
