Nothing brightens your mood quite like a sunny day�clear blue skies, birds chirping, not a care in the world.

Likewise, nothing dampens your mood like a rainy day�overcast skies, a cold wetness weighing you down physically and mentally.

Except� this isn�t exactly true.

Sure, occasionally a study will find that people report being happier on sunny days[1]. This seems to affect their behavior as well, as stock markets are more likely to go up on days when the local weather is nice[2], and people are more generous toward others when the sun is out[1].

Also, regular exposure to sunlight can prevent Seasonal Affective Disorder[3]�so, over longer periods at least, sunnier weather can lead to sunnier dispositions.

But, on a day-to-day basis, whether it�s cloudy or the sun is shining has little practical impact on the mood of most people in industrialized nations. We know this from large-scale studies[4], reviews of smaller studies[5], and analysis of massive amounts of social media data[6].

Why not? There are three reasons why a sunny day is less beneficial than you might think.

1. People get used to nice things

Yes, sunshine can make you happy. But, this doesn�t last forever. That�s because you get used to it.

For example, people who live in sunny parts of California report no greater satisfaction with their lives than people who live in cloudy parts of New England[5]. Likewise, the effect of a sunny day on the stock market gets smaller the closer you get to the equator, where it�s sunny more of the time[7].

The same goes for the effects of daily weather in different seasons. In the spring, after a long, cold winter, a sunny day can thaw both the snow and a person�s heart. But, in the summer, when sunlight is generally abundant, whether it�s sunny or cloudy does little to change a person�s mood[4].

2. The sun is hot

When temperatures rise, people start to become uncomfortable and irritated. They grow impatient and are more prone to lash out[4].

That�s another reason why a sunny day isn�t necessarily better than a cloudy day in the summer[4]. Sometimes, it�s cooler, and thus more comfortable, when it�s cloudy.

3. People work indoors

Great weather is great� when you can enjoy it. Unfortunately, most people in the industrialized world spend their days indoors.

When the weather is nice and a person is outside, they do indeed report greater happiness. But when a person is stuck inside on a nice day, they almost seem to resent the weather�reporting less happiness on sunny days[4]!

Keep in mind these three factors if you want the emotional benefits of a sunny day. Do the following:

• Make a conscious effort to be grateful for nice weather, even if it�s been nice all week. (If you need help, call to mind days when the weather was terrible.)
• If it�s too hot out, limit your time outside, or head for shade.
• Even if you have to work inside on a nice day, be sure to step outside for sunshine at least once.

R?eferences

1. Cunningham, M.R. (1979). Weather, mood, and helping behavior: Quasi experiments with the sunshine samaritan. Journal of Personality and Social Psychology, 37, 1947.

2. Hirshleifer, D., & Shumway, T. (2003). Good day sunshine: Stock returns and the weather. The Journal of Finance, 58, 1009�1032.

3. Wirz-Justice, A., Graw, P., Kr�uchi, K., Sarrafzadeh, A., English, J., Arendt, J., & Sand, L. (1996). �Natural� light treatment of seasonal affective disorder. Journal of Affective Disorders, 37, 109-120.

4. Keller, M.C., Fredrickson, B.L., Ybarra, O., C�t�, S., Johnson, K., Mikels, J., � Wager, T. (2005). A warm heart and a clear head: The contingent effects of weather on mood and cognition. Psychological Science, 16, 724�731.

5. Lucas, R.E., & Lawless, N.M. (2013). Does life seem better on a sunny day? Examining the association between daily weather conditions and life satisfaction judgments. Journal of Personality and Social Psychology, 104, 872�884.

6. Li, J., Wang, X., & Hovy, E. (2014, November). What a nasty day: Exploring mood-weather relationship from Twitter. In Proceedings of the 23rd ACM International Conference on Conference on Information and Knowledge Management (1309-1318).

7. Keef, S.P., & Roush, M.L. (2007). A meta?analysis of the international evidence of cloud cover on stock returns. Review of Accounting and Finance, 6, 324�338