5 . How Weather Affects Our Mood

The weather supplies many metaphors (隐喻) for our changeable minds. Moods can brighten and darken, futures can be under a cloud, and relationships can be stormy.    1    , but does it also influence our moods?

Of the many aspects of weather, sunshine is the most closely tied to mood. Although the link is weaker than many people imagine, sunlight has repeatedly been found to increase positive moods and reduce tiredness.    2    . Happy people tend to be more favorable toward one another, and people are more helpful when the sun is shining. One study even found that diners in Minnesota, US, tipped more generously on sunny days.

    3    . A study showed that university admissions officers stressed the academic qualifications of applicants more on cloudy days, and their non-academic qualities more on sunny ones.

    4    . The more it departs (偏离) from an ideal of around 20C, the more discomfort we feel. One study found that rates of helping others decreased as temperatures dropped below or rose above this value.

Indeed, the effects of weather on mood depend on our behavior and on how we think.     5    . A study by US psychology researcher Matthew Keller and his colleagues showed that beneficial effects of warm and sunny conditions on mood were only seen in people who had spent more than 30 minutes outdoors that day. Good weather even had negative effects on mood for people confined (限制) indoors, who perhaps looked enviously (嫉妒地) outside at the solar fun they were missing.