The happiest country on Earth: The winner is ...

Jane Onyanga-Omara
A scenic view in Helsinki, Finland.
Scanrail | iStock / 360 | Getty Images

If you want to be happy, move to Finland.

The Nordic country renowned as the Land of the Midnight Sun is No. 1 in the World Happiness Report released Wednesday by the United Nations.

Finland boasts long, dark winters and short summers bathed in almost continuous light, and came in fifth place last year.

"The Finns definitely fall into the contentment range of the scale," Eric Weiner wrote in his 2008 book The Geography of Bliss: One Grump's Search for the Happiest Places in the World, adding that this wasn't the "American idea of overflowing with joy."

"Northern European countries, where the emotional range is more modulated — in the sense that they're humming along at fairly high levels, but don't have the (emotional) peaks and valleys that other European countries have — score higher (on happiness)," he added, according to the BBC.

Following Finland in the top 10 are Norway, Denmark, Iceland, Switzerland, Netherlands, Canada, New Zealand, Sweden and Australia.

The report, released ahead of the United Nations World Happiness Day on March 20, ranked 156 countries on six variables — income, life expectancy, freedom, social support, trust and generosity. The report included surveys of 117 nations based on the happiness of immigrants there. Finland came out on top in both categories.

The same countries over the past two years have been in the top 10 spots. They are characterized by lower wealth inequality, high taxes, good access to healthcare, long life expectancy, low corruption and support for those who need help from the state or communities.

The U.S. nabbed the 18th spot, down four places from last year. Top factors for the American decline in happiness include weakened social support networks, government and business corruption and a declining confidence in public institutions. The report also cites obesity, the opioid epidemic and depression as other issues affecting Americans' happiness.

A main focus this year was migration and the happiness of immigrants, included in the report for the first time. The 10 overall happiest countries were also listed in the top 11 for the happiness of their immigrants.

Of the 5.5 million people living in Finland, about 300,000 are immigrants.

Meik Wiking, chief executive of the Happiness Research Institute, an independent think tank based in the Danish capital Copenhagen, said the the high-ranking Nordic countries "are doing something right in terms of creating good conditions for good lives."

He said the immigrant happiness finding "shows the conditions that we live under matter greatly to our quality of life, that happiness is not only a matter of choice."

"The most striking finding of the report is the remarkable consistency between the happiness of immigrants and the locally born," said one of the report's editors, John Helliwell, of the University of British Columbia.

He said although immigrants move from countries with varying levels of happiness, in their new homes their happiness levels become similar to those born locally. "Those who move to happier countries gain, while those who move to less happy countries lose," Helliwell said.

Topping the list of least happy countries are Burundi, Central African Republic and South Sudan, where political turmoil exists, incomes are low and access to adequate healthcare is difficult.

The report, published by the U.N. Sustainable Development Solutions Network and funded in partnership with the Ernesto Illy Foundation, is the sixth since 2012.

These are the world's happiest countries:

1. Finland

2. Norway

3. Denmark

4. Iceland

5. Switzerland

6. Netherlands

7. Canada

8. New Zealand

9. Sweden

10. Australia

And the least happy countries:

1. Burundi

2. Central African Republic

3. South Sudan

4. Tanzania

5. Yemen

6. Rwanda

7. Syria

8. Liberia

9. Haiti