New Zealand's South Island is currently under a Strong Wind Watch for Monday, September 1, 2025. Exposed areas in Dunedin, Clutha, Southland, and Stewart Island may experience west to southwest winds nearing severe gale force. There is a moderate chance this alert could be upgraded to a full warning, indicating a period of significant weather activity.
The preceding weekend saw the North Island contend with considerable weather disruptions. Across Auckland, Waikato, and the Bay of Plenty regions, Fire and Emergency services responded to over 100 incidents, primarily due to fallen trees and power lines. Auckland alone recorded 114 weather-related call-outs, with no injuries reported.
Looking ahead, the seasonal outlook for the North Island suggests a 60% probability of above-average temperatures and a 50% chance of increased rainfall through October. This forecast points to a higher likelihood of substantial rainfall events as the nation transitions into spring.
New Zealand's susceptibility to strong winds is well-established, largely due to its geographical position within the 'Roaring Forties,' a belt of strong westerly winds in the Southern Hemisphere. Historically, events like the Wahine storm in April 1968, which resulted in 53 fatalities, and Cyclone Bola in March 1988, which brought hurricane-force winds and severe flooding to the North Island's east coast, highlight the potential for destructive wind events. More recent extreme wind events in Taranaki and Greymouth in July 2007 and July 2008, respectively, have been studied for their impact on infrastructure, underscoring the ongoing challenge of wind-related damage.
The nation's infrastructure, including roads and power lines, remains particularly vulnerable to these weather patterns. Strong winds can compromise structural integrity and disrupt essential services, as demonstrated by the numerous power outages and downed lines reported during the recent weekend. The Insurance Council of New Zealand has reported significant insured weather-related losses, amounting to nearly $800 million between 2013 and 2017, excluding uninsured losses or service disruptions.
Efforts are underway to bolster resilience, with initiatives like the New Zealand Wind Engineering Consortium aiming to enhance the understanding and mitigation of severe windstorm impacts through data analysis and improved modeling. This proactive approach is vital as climate change may further influence the intensity and frequency of extreme wind speeds.