Researchers in Germany sought to find out whether day-to-day weather affects people's moods.
Researchers branched out beyond just sunny and cloudy and looked at temperature, wind, sunlight, rain and snow, air pressure, and how long the days were.
The study was led by Jaap Denissen of Humboldt University in Berlin.
The study had 1,233 participants, all living in Germany at the time. Most of the participants were women, the average age was 28, with ages spanning from 13 to 68 years old.
Study participants were first given a personality test that measured extraversion, neuroticism, how open one is to experiences, and how agreeable and conscientious they are.
Then, participants were given a daily online diary and asked to respond to a questionnaire that measured tiredness and positive and negative mood. Examples of positive mood included feeling "active," "alert," "attentive," "excited." Examples of negative mood included feeling "irritable," "scared," "upset," "guilty." Tiredness was measured by terms such as "sluggish," "sleepy," and "drowsy."
Most of the participants began the study in the fall.
Researchers looked at how much the participants socialized and slept, getting feedback on those conditions, which can affect mood.
They also collected daily weather data and matched it to the participants' ZIP codes.