A chilly climate isn’t keeping Norway from basking in the glow of being named the world’s happiest country on Monday.It surged from fourth place in last year’s UN assessment all the way to the top spot, according to the World Happiness Report 2017.Other top countries on the list included Nordic neighbours Denmark and Iceland, as well as nearby Switzerland.“All of the top four countries rank highly on all the main factors found to support happiness: caring, freedom, generosity, honesty, health, income and good governance,” the summary explained.Rounding out the top 10 were Finland, in fifth place, the Netherlands, Canada, New Zealand, and Australia and Sweden tied for ninth. The entire top 10 were affluent, developed nations, although money is not the only ingredient for happiness, the report said.In fact, among the wealthier countries the differences in happiness levels had a lot to do with “differences in mental health, physical health and personal relationships: the biggest single source of misery is mental illness,” the report said.“Income differences matter more in poorer countries, but even their mental illness is a major source of misery,” it added. Another major country, China, has made major economic strides in recent years. But its people are not happier than 25 years ago, the report found. China ranked 79th in the study of 155 countries.The United States meanwhile slipped to the number 14 spot due to less social support and greater corruption – the very factors explaining why Nordic countries fare better on the happiness scale.Norwegian Prime Minister Erna Solberg welcomed the report as “a nice validation on a Monday morning. For many years, Norway has been behind Denmark in this ranking. I’ve made a point of it in many dinner speeches in the Nordics. Now I must find something new!” she said in a message on Facebook in Norwegian.“But even if we top this statistic now we continue to prioritize mental health care, to improve follow-up of children and young people because many are still struggling.”The World Happiness Report 2017 was released by the United Nations on the International Day of Happiness. It is the fifth such report since the first was published in 2012.“Since then we have come a long way. Happiness is increasingly considered the proper measure of social progress and the goal of public policy,” the report said.While the 10 countries at the top remained the same as in a 2016 update, those in the bottom 10, which had the lowest life evaluations, showed greater variation.The Central African Republic, which returned to the surveyed group, came in dead last at 155, with Burundi and Tanzania doing only slightly better.Among the 20 largest losers, five were in the Middle East and North Africa and five were in sub-Saharan Africa.