Can the secret to the country’s happiness be found in its communal pools? If you use suicide rate as an indicator, Iceland doesn't seem to be so happy. https://en.wikipedia.org/wiki/List_of_countries_by_suicide_r...
Iceland gets next to no sun November-February, leading people to depression, drinking, etc. It would likely affect you much more than the winter you know from other countries. If anything, the social aspect of going to a hot pool in the winter is likely to keep people from committing more suicides.
I think a lot of these "Isn't Iceland wonderful" articles are poorly sourced pop-science junk designed to get ad impressions. Iceland has a lot of problems and is a much more complex country than many give it credit for. Its not a bunch of elf worshippers living in the forest. They're a complex modern people with all the problems modernity brings. I also believe a lot of people with leftist political beliefs don't want to discuss the downsides of the Scandinavian welfare state as these criticism are, of course, critical of their own personal politics. So narratives that are critical of these politics don't get upvoted on sites like HN and Reddit which are largely left-leaning.
Its also worth mentioning that national happiness is tied very closely with income inequality, not pools. Even then, you can have a high level of general happiness and still have a relatively high suicide rate for reasons not fully understood, but I imagine self reporting of how 'happy' you are isn't granular enough to really tell us very much.
There's an ugly "noble savage" narrative to Icelandic people that I personally find offensive. I wish the media would stop pushing that narrative but I can understand that it gets ad impressions the same way Native American "noble savage" stories were so popular a hundred years ago in the USA. The reality is that both are reductionist and inaccurate and gloss over the very significant negative aspects of both their cultures.
Cites:
https://en.wikipedia.org/wiki/List_of_countries_by_suicide_r...
http://www.oecd-ilibrary.org/sites/9789264183896-en/03/11/in...
http://healthland.time.com/2011/04/25/why-the-happiest-state...