Now that April is here, baseball season has returned and spring begins to take hold. People are excited that better weather will help them shake the winter doldrums and "improve their mood."
But while many people express these sentiments, it raises the question of whether the data back up such assumptions. Do our moods and self-evaluations actually improve with the arrival of spring and summer?
This question is complex and eludes a simple yes-or-no answer. For example, it is clear that weather strongly influences people who suffer from seasonal affective disorder (SAD). They often experience a depressed affect in winter that abates with the arrival of spring, primarily because of increased daylight (Oren et al., 1994). So for people who suffer from SAD, yes, better weather is a blessing indeed.
Yet when it comes to other people, the scientific literature has found that the weather-mood link is small—and sometimes surprising (e.g., Keller et al., 2005). For example, Deniseen et al. (2008) studied more than 1,600 people, examining daily reports of their well-being along with local weather station conditions (e.g., temperature, sunlight, wind conditions). The findings were interesting in that none of the weather measurements significantly predicted positive affect (e.g., feeling enthusiastic, inspired, determined). There was, however, evidence that negative affect (e.g., feeling jittery, distressed, irritable) increased with warmer—and not colder—temperatures, and decreased with more sunlight and less wind. Overall, the effects were small, and the findings observed indicated that although weather was unrelated to people's positive affect, warmer temperatures actually increased people's negative feelings, even though more sunlight, as one might expect, had a more desirable effect—but again, the effects were modest in size.
However, it is likely that better weather provides us with other, indirect benefits. For example, nicer weather often allows people to get outside to exercise and commune more with nature. Having urban residents spend 90 minutes walking through a park resulted in people showing less ruminative thinking and exhibiting more healthy brain activity (Bratman et al., 2015). Similarly, research has shown that hikers show 50% boosts in creativity after just a few days of hiking while being disconnected from technology (Atchley et al., 2012). Thus, even if the weather itself does not produce significant direct benefits for individuals, getting outside because of nicer weather can improve our health and mental performance through greater connection with nature and more exercise.
What about summer love?
Does better weather lead to the initiation of new romantic relationships? There is a belief that spring and summer are the seasons for love, while fall is when depressing break-up songs earn their popularity. Interestingly, Facebook can provide some insight into this issue in that the website tracks changes in relationship status across the calendar (albeit an imperfect measure of romantic relationship initiation and dissolution). Some interesting trends emerged in a study of users in the United States by Facebook researchers in 2012: More relation dissolutions occurred during the summer—June was the worst month for Facebook users' relationships, regardless of user age—while the days with the most "new relationships" occurred in February, right after Valentine's Day. In short, if Facebook is a barometer of relationships, summer weather brings about the demise of relationships, not their flourishing. Maybe the dissolution of some relationships is a cause for joy, but only a true cynic would conclude that breakups, on average, bring people greater happiness.
Summer is prime time for crime
One final note about summertime: In addition to its being a potentially bad time to maintain a romantic relationship, it also tends to be a period when more antisocial behavior occurs. In a classic study by Anderson and Anderson (1984) examining crime data in Houston, the number of aggressive crimes (e.g., murder, rape) went up as the temperature rose. Similar data emerged from examining more than 5 million publicly available crime reports in Chicago since 2001 (van Zanten, 2016). These data show that for violent crimes like assault, robbery, sexual assault, and battery, there is a strong linear trend of more of these crimes occurring as the temperature increases from cold (20°F) to warm (90°F).
Clearly, such weather-crime findings have alternative explanations (e.g., warm weather may simply increase the amount of contact that people have with others that is necessary for person-on-person crime activity rather than warmer temperatures causing antisocial behavior directly). However, controlled laboratory research has repeatedly shown that hot temperatures increase hostile thoughts and feelings that trigger aggressive actions (Anderson et al., 1995).
Overall, it is interesting that although people instinctively believe that better weather results in better moods, the evidence for this assumption is weak. In general, the effects of "better weather" on people's feelings are modest, inconsistent, and at times counter to commonly-held expectations. Moreover, warm weather seems associated with breakups and more antisocial behavior. Yet there can be benefits, not only directly for people who suffer from SAD, but via indirect effects when people get out in nature and exercise more. As with many assumptions in life, presumed cause-effect relations can be wrong. Often, the key to experiencing benefits depends on what people do with their opportunities rather than whether they simply have them in the first place.
Anderson, C. A., & Anderson, D. C. (1984). Ambient temperature and violent crime: Tests of linear and curvilinear hypotheses. Journal of Personality and Social Psychology, 46, 91-97.
Anderson, C. A., Deuser, W. E., & DeNeve, K. M. (1995). Hot temperatures, hostile affect, hostile cognition, and arousal: Tests of a general model of affective aggression. Personality and Social Psychology Bulletin, 21, 434-448.
Atchley, R. A., Strayer, D. L., & Atchley, P. (2012). Creativity in the Wild: Improving Creative Reasoning through Immersion in Natural Settings. PLoS ONE 7(12): e51474.
Bratman, G. N., Hamilton, J. P., Hahn, K. S., Daily, G. C., & Gross, J. J. (2015). Nature experience reduces rumination and subgenual prefrontal cortex activation. Proceedings of the National Academy of Sciences, 112, 8567-8572.
Denissen, J. J. A., Butalid, L., Penke, L., & van Aken, M. A. G. (2008). The effects of weather on daily mood: A multilevel approach. Emotion, 8, 662-667.
Facebook (March 21, 2012). The right time for love: Tracking the seasonality of relationship formation. Retrieved from https://www.facebook.com/notes/facebook-data-science/the-right-time-for-....
Keller, M. C., et al. (2005). A warm heart and a clear head: The contingent effects of weather on mood and cognition. Psychological Science, 16, 724-731.
Oren, D., Moul, D., Schawartz, P., Brown, C., Yamada, E., & Rosenthal, N. (1994). Exposure to ambient light in patients with winter seasonal affective disorder. American Journal of Psychiatry, 151, 591–593.
van Zanten, E. (April 3, 2016). Chicago crime vs. weather. Retrieved from http://crime.static-eric.com/.