Swiss Re has released new data highlighting hurricane activity trends as the 2025 Atlantic hurricane season enters its final weeks.
The company’s analysis follows discussions at the recent APCIA conference, where property and casualty industry leaders noted the season’s relatively quiet conditions so far.
Swiss Re’s data shows that during the past five hurricane seasons (2020-2024), 20 hurricanes and 11 major hurricanes formed in the second half of September or later.
Notable storms in this period include Hurricane Ian in 2022, which reached Category 5 status after forming on September 23, Hurricane Helene in 2024 (Category 4, formed September 24), and Hurricane Milton in 2024 (Category 5, formed Oct. 5).
In 2020, six hurricanes and five major hurricanes developed in October and November, underscoring the potential for significant activity late in the season. Swiss Re also notes that several major hurricanes in recent history have formed in late September or beyond, including Michael in 2018 (Category 5, formed October 7), Maria in 2017 (Category 5, formed September 16), Sandy in 2012 (Category 3, formed October 22), Wilma in 2005 (Category 5, formed October 15), and Rita in 2005 (Category 5, formed September 18).
“It only takes one storm to make a hurricane season memorable, and that storm may form late in the season," said Monica Ningen (pictured above), CEO of P&C Reinsurance US at Swiss Re. "Hurricane Sandy in 2012, which developed in late October and devastated the Northeast, is a clear reminder. In many recent years, major hurricanes have formed in mid-September or later.
“Even now, storms remain active in the Atlantic, so the final stretch of the season through November requires the same vigilance and readiness as the peak. We always hope for the best, but preparation is vital,” Ningen said.
Severe weather events in 2025 have contributed to significant insured losses, with the North American monsoon in late September causing widespread flooding in Arizona. According to Aon, insured losses from this event are projected to reach hundreds of millions of dollars, adding to a broader trend of high catastrophe losses this year.
Industrywide, losses from August storms in the US are also expected to run into the hundreds of millions of dollars. Multiple rounds of severe weather affected the north-central US and Chicago area, with the absence of a major landfalling hurricane so far this season providing only temporary relief for insurers.
In Canada, secondary perils such as wildfires, floods, and hailstorms now account for nearly 90% of insured catastrophic losses. Swiss Re’s Canada reinsurance CEO Jolee Crosby said this marks a permanent change in risk modeling and pricing, as the frequency and severity of these events continue to rise.
Swiss Re’s analysis indicates that, despite a lack of landfalling storms so far this year, the risk of significant hurricane activity persists through the end of November. The company emphasizes the importance of continued vigilance and preparedness for the remainder of the season.
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