Unusually violent weather throughout the U.S. and the Pacific Rim made 2004 one of the most active years for natural phenomena in recent memory, according to a recently-released Aon report.

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Aon's 2004 Global Climate and Catastrophe Report, produced by Aon Re Global and Impact Forecasting, LLC, subsidiaries of Aon Corporation (NYSE: AOC), depicts a year of freakish weather patterns, ending with the worst natural disaster in modern times: the December 26th tsunami. The earthquake-driven massive sea wave killed more than 159,000 people across Sri Lanka, Indonesia, and India and obliterated villages and seaside resorts in ten countries across southern Asia and eastern Africa. By contrast, the worst natural disaster in 2003 was the Bam, Iran earthquake in which 26,271 people perished.

The 2004 hurricane season in the U.S. was among the most active on record. The western Atlantic produced 15 named storms and 9 hurricanes, which is above the norm of 10 tropical systems and 6 hurricanes. The United States and Caribbean Islands experienced a rough August and September, with 6 major hurricanes making landfall in 2004, well above the average normal landfall of 1-2 storms. By contrast, 2003 saw only two of seven hurricanes making landfall. It had been half a century since Florida sustained hits by three destructive hurricanes in rapid succession. In 1950, hurricanes Baker and Easy made landfall in or near Florida within a six-day period.

The United States tornado season was also especially busy in 2004. The tropical storms that battered the southern part of the country were partially responsible for the higher incidence of tornadoes last year. The higher-than- usual number of hurricanes helped to spawn some of the 1,722 tornadoes in the United States in 2004, according to the Storm Prediction Center in Norman, Oklahoma. That's up from the previous year's total of 1,376. A normal tornado season yields an average of 1,200 tornadoes.

Of the 1,722 storms in 2004, 20 were so-called "killer" tornadoes, resulting in 36 deaths. That's down from 2003's 23 "killer" storms and 54 fatalities. Both years were below the normal count of 25 "killer" storms resulting in an average of 54 deaths nationwide.

Aon's report indicates at least one category showed some improvement. There were fewer typhoons than normal in the western Pacific Ocean. That region generated 21 typhoons in the 2004 tropical season, lower than the average 27. In 2003 there were 17 typhoons. Japan was struck by seven tropical systems, four of which were typhoons. This represents the most typhoon landfalls in Japan since 1982.

Aon Re Global and Impact Forecasting's annual report, issued during the first month of every year, analyzes the current state of the world's climate and summarizes the past year's natural catastrophes. According to the report, 2004's climate across the globe was warmer and wetter than normal, which is a change from previous years, where warmer but drier than normal conditions existed. Precipitation amounts were also higher than normal for the first time in four years. Though many areas still experienced drought conditions, some locations received an overabundance of rain, leading to severe flooding that killed thousands of people this last year, primarily across Southeast Asia and through the Caribbean Sea.

Aon Re Global and Impact Forecasting's annual report also summarizes 2004's record-breaking natural disasters, many of which broke long-standing records. Haiti and the Dominican Republic were hit with two massive flooding events in 2004, killing over 5,000 people in May and September combined. Monsoon flooding across Bangladesh, India, and China claimed more than 1,900 lives from late June through early August. Landslides and flooding from successive tropical systems killed thousands of people in late November in the Philippines.

Impact Forecasting, LLC is a wholly owned subsidiary of Aon Corporation. Impact Forecasting's staff of science, finance and insurance professionals model and analyze the financial implications of natural catastrophes to help clients make risk management decisions.

Aon Re Global provides traditional, alternative risk transfer and capital markets based reinsurance advisory and execution services to insurers and reinsurers. Aon Re Global's client advisory services include dynamic financial analysis, rating agency capital modeling assistance, capital allocation and optimization services, catastrophe modeling services, regulatory assistance, tax planning and capital markets structuring and placement services.

Aon Corporation ( http://www.aon.com/ ) is a leading provider of risk management services, insurance and reinsurance brokerage, human capital and management consulting, and specialty insurance underwriting. The company employs approximately 51,000 professionals in its 600 offices in more than 120 countries. Backed by broad resources, industry knowledge and technical expertise, Aon professionals help a wide range of clients develop effective risk management and workforce productivity solutions.

This press release contains certain statements relating to future results, which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from either historical or anticipated results, depending on a variety of factors. Potential factors that could impact results include the general economic conditions in different countries around the world, fluctuations in global equity and fixed income markets, exchange rates, rating agency actions, resolution of pending regulatory investigations and related issues, including those related to compensation arrangements with underwriters, pension funding, ultimate paid claims may be different from actuarial estimates and actuarial estimates may change over time, changes in commercial property and casualty markets and commercial premium rates, the competitive environment, the actual costs of resolution of contingent liabilities and other loss contingencies, and the heightened level of potential errors and omissions liability arising from placements of complex policies and sophisticated reinsurance arrangements in an insurance market in which insurer reserves are under pressure. Further information concerning the Company and its business, including factors that potentially could materially affect the Company's financial results, is contained in the Company's filings with the Securities and Exchange Commission.

   Contact:
   Al Orendorff
   312-381-3153
   http://www.aon.com/newsroom

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SOURCE: Aon Corporation

CONTACT: Al Orendorff of Aon Corporation, +1-312-381-3153

Web site: http://www.aon.com/
http://www.aon.com/newsroom