The arrival of springtime and a new lease of life and energy. Factors, like daylight and temperature and the additional hours of sunlight and rising warmth, increase in most cases the levels of serotonin and dopamine - the chemicals responsible for feelings of well-being.
The cultural events and festivals not to forget some spring breaks, give people a positive outlook.
Seasonal cues, like flowers, are triggering our senses and can cause us to relive these moments year after year. These factors conspire to make us feel more positive in springtime.