This year is likely to be the ninth warmest on record, with global temperatures in 2012 cooler than the average for the past decade owing to the effects of La Niña weather patterns early in the year.
The estimates come as governments wrangle over the form of a proposed new global agreement on climate change, that could eventually replace the Kyoto protocol. Nearly 200 countries are meeting in Doha, Qatar, but as yet there are few signs of unity.
So far this year, the current world average global temperature is 14.45C, which is between one-tenth and a 0.5C higher than the 1961 to 1990 average.
The World Meteorological Organisation (WHO) used information from three global temperature sets, running from January to October, to make its estimate. But the ranking could change under further analysis, and final data will not be ready until next March.