Research shows that 20 minutes of fresh air has a strong effect on the feeling of happiness. In fact, it also improves memory and thinking capacity. If you can also make sure you get out for a little while in a non-urban environment, it has an even greater effect on happiness.
It should preferably be in a forest or by the sea, but a park also works, says author Shawn Achor in his book The Happiness Advantage, according to the Times.
The temperature of the outdoors also affects how effective the outdoors is for happiness. According to a study by the American Meteorological Society, temperature is more important than, for example, wind speed and humidity. The optimal temperature seems to be 13.9 degrees.