Only 2005, 1949, 2004 and 2003 posted higher temperatures, it said in a statement, adding that so far this year temperatures have been 1.0 degree Celsius above the 1961-1990 average.

Last year the country logged its driest year since records began although this January began with snow falling in the capital Lisbon for the first time since 1954.

But the cold start to the year was followed by a scorching summer that gave way to a mild and unusually wet autumn and winter.

A heatwave in July caused night-time temperatures to stay at or above a tropical 20 degrees Celsius (68 degrees Fahrenheit) across much of the country, causing beaches to be packed with bathers, while outdoor cafe patios have remained full even in winter in Lisbon.

Many scientists believe that greenhouse gases such as carbon monoxide, which are produced when fossil fuels like oil and natural gas are burnt, are flowing into the atmosphere at an unprecedented rate and are warming the Earth.

Earlier this month both Spain and the Netherlands reported that 2006 was set to be their warmest year since records started being kept.