Morning people are generally happier than those who prefer late nights, according to a new Canadian study.
The researchers also found teenagers are grumpiest in the morning, and as we age, we start to enjoy mornings more, which apparently makes us happier.
The study compared two groups 435 people aged 17 to 38 and 297 people aged 59 to 79.
Both groups answered questionnaires about their emotional state, how healthy they feel and their preferred time of day.
The researchers found only seven percent of young adults like mornings, but by the time we turn 60, 93 percent of us prefer mornings.
"We found that older adults reported greater positive emotion than younger adults, and older adults were more likely to be morning-type people than younger adults," Renee Bliss, a graduate student at the University of Toronto who led the study, told LiveScience. "The 'morningness' was associated with greater happiness emotions in both age groups."
The morning people tended to say they felt healthier than night owls, which the researchers attributed to them getting better sleep, which has a positive impact on the immune system.
"We don't know why this is, but there are a few potential explanations. Evening people may be more prone to social jet lag; this means that their biological clock is out of sync with the social clock," Biss said.
"Society's expectations are far more organised around a morning-type person's schedule. An evening person may go through their week feeling unhappy because they have to get up earlier than they would like to."
If you want to feel perkier, Bliss suggests going to bed earlier and getting some sun exposure every day.
"One way to do it is to increase your natural light exposure early in the morning, and to wake up earlier and go to bed earlier," Biss said. "It's easiest if you have a consistent schedule, to make sure you are waking up at the same time every day."
The study was published in the May issue of the journal Emotion.