WMO and BoM Confirm Weak La Niña Underway, Set to Influence Global Weather into 2026

Key facts

• The World Meteorological Organization (WMO) says there is a 55 per cent probability of a weak La Niña over the next three months.
• The Bureau of Meteorology (BoM) confirms La Niña has emerged and is now firmly established in the tropical Pacific.
• The latest Niño3.4 SST index for the week ending 23 November is −0.93 °C, with sustained values below −0.8 °C signalling La Niña.
• The 30-day SOI was at +16.1 and the 90-day value was at +8.5, with sustained readings above +7.0 confirming the La Niña pattern.
• The negative Indian Ocean Dipole (IOD) remains active but has weakened to −0.60 °C and is predicted to return to neutral in December.
• Sea surface temperatures in the Australian region were the second warmest on record for October and are likely to persist into early 2026.
• From December 2025 to February 2026, temperatures are expected to remain above normal across much of the Northern and Southern Hemispheres.
• For India, this could mean a cooler winter in the north, more frequent western disturbances and a higher chance of stronger systems forming in the Bay of Bengal.