Wintertime is rough on those whom the 19th-century hiker-philosopher John Muir called “tired, nerve-shaken, over-civilized people.” But we have an obvious cure for our doldrums: go outside. Though we are months away from the flowers and leafy foliage of spring, a dose of nature can still calm the mind and solidify human bonds. The real question is why we don’t partake more often of this easy balm.

To better understand how our everyday routines contribute to our happiness, the British environmental economist George MacKerron launched an iPhone app in 2010 called Mappiness. Within a year, the app was pinging some 20,000 volunteers a few times a day to find out what they were doing, where they were doing it and how they felt about it.

After crunching the data, Dr. MacKerron and Susana Mourato of the London School of Economics and Political Science published their findings in the journal Global Environmental Change in 2013. They found, unsurprisingly, that people are least happy at work or while sick in bed and most happy when they’re with friends or lovers.

But one of the biggest variables for their subjects (who tended to be young, employed and educated) was where they were. They were significantly happier outdoors, especially in natural settings, than they were indoors, even when the researchers tried to control for the effects of being at work.

But there was a catch: Most of the participants didn’t behave as if they knew this, because they were rarely outside. They were indoors or in vehicles for 93% of their waking hours.