This year will mark a record run of six straight years of multi-billion-dollar payouts for global insurers due to wildfires, Aon says.

The total direct economic costs from record-breaking wildfires across California, Oregon and Washington are likely to reach well into the billions of dollars, Aon’s latest Global Catastrophe Recap report for September says.

The US has reported 22 fires so far this year, with at least 100,000 acres (40,468 hectares) burned - a record since the statistic was first tracked in 1997. In California alone, five of the state’s six largest fire events since 1932 were recorded in August and September, along with five of the state’s top 20 most destructive fires on record.

“The wildfires … ensured a record sixth consecutive multi-billion-dollar payout year for global insurers with this peril,” Steve Bowen, director and meteorologist at Aon, said. “This comes as the industry continues to put more focus on the increased annual costs arising from secondary perils."

The third quarter is historically the costliest of the year given the peak of tropical cyclone season in the Atlantic and Pacific Ocean Basins.

While September did result in notable storm landfalls in the US, Belize, South Korea, and Portugal, Mr Bowen noted that “acres burned left a lasting impact in the Western United States”.

In Alabama, Hurricane Sally came ashore on September 16 as a Category 2 storm, killing eight and clocking up total economic losses estimated at more than $US5 billion ($6.97 billion), while public and private insurance losses exceeded $US2.5 billion ($3.48 billion).

On September 21, tropical Storm Beta made landfall, bringing heavy rainfall and flash flooding to coastal Texas and Louisiana. One of the top five wettest three-day rainfall totals on record in Houston was recorded, with total economic losses of over $US100 million ($139.37 million).

Seasonal monsoon flooding persisted in China, with deadly flooding in some areas the worst since 1998. Combined economic losses were likely to exceed CNY220 billion ($44 billion).

In Greece, rough seas, damaging winds and flooding rainfall hit western and southern regions between September 17-20 costing more than $US100 million ($139.37 million).

Hurricane Nana made landfall on September 3, bringing flooding rains to portions of Belize, Honduras, Guatemala and southern Mexico, costing tens of millions of dollars.

Typhoon Maysak made landfall in South Korea on September 3 and later affected the eastern parts of North Korea, China and Russia. A few days later, Typhoon Haishen came ashore near the coastal city of Ulsan, South Korea. Economic losses from each of the storms were estimated at more than $US100 million ($139.37 million).

No major natural disaster events were recorded in Australia and New Zealand during the month of September.