It came just below 2003, 2002 and 1998, with the average world temperature exceeding by 0.44 degrees Celsius the 14 degrees (57 degrees Fahrenheit) for the 30 years between 1961 and 1990.
But October 2004 was the warmest October on record, indicating that the phenomenon of global warming was continuing.
In the northern hemisphere the mean temperature was 14.60 degrees and in the southern hemisphere 14.27 degrees, the effect of heatwaves in central Asia, China, the eastern United States and Alaska, and over much of the Atlantic Ocean, the WMO said.