As Ernest Hemingway once wrote, "When spring came, even the false spring, there were no problems except where to be happiest."
Aside from being a master of words, Hemingway also has the benefit of being right about the season's effect: Spring fever is probably real. If you've noticed a little extra something in your step because of the weather, it's no coincidence. Warmer days have a direct influence on your mood and behavior.
Below are just some of the ways toasty temperatures affect your attitude:
1. Being outdoors in the sun is linked with a mood boost...
The gold standard on this subject is a 2004 University of Michigan study that found people who spent at least 30 minutes outside in pleasant weather — either by taking a trip to warmer climates in the winter months or by taking advantage of a newly warm spring day in the park — had happier moods. And in corroborating research, a 2014 UM study found that being outside could lead to a better mindset and reduced stress.
But if you’re still stuck in the tundra, don’t worry too much. Kelly Rohan, a professor of psychiatric science at the University of Vermont, points out that weather pales in comparison to other stress mitigators, such as the lessening of relationship or work pressures. While warmer weather doesn’t make a sizable difference in outlook, research supports the idea that nice weather has a positive psychological impact on the overall population, she told HuffPost.
2. ...But it may not be that way later in the summer.
The weather-mood connection is a positive one, up to a point. The original University of Michigan researchers also noted that positive attitudes seemed to wilt in particularly sweltering weather — an idea that’s also supported by other research conducted on climate and mood change.
Despite the fact that summer brings sunnier days and brighter colors, people are at a greater risk for heatstroke and dehydration during the warmer months, Brent Solvason, a Stanford University clinical associate professor of psychiatry and behavioral sciences, told HuffPost.
“There’s clearly a sense of discomfort because of the oppressiveness of the heat,” he said. Both dehydration and heatstroke can have an influence on mood or behavior and, at their worst, can also damage the brain.
3. You’re generally happier when the days are longer.
Daylight Saving Time may have brought a series of grumbles — “What do you mean we lose an hour of sleep?!” — but it does have one positive perk: More sunlight.
“People simply feel better on longer days and when there’s more available sunshine,” Rohan said. “The winter variety of seasonal affective disorder (SAD) is mostly tied to how long the day is. So even though spring was a little slow coming this year... the days are still long. Those extra hours of sunlight make a really big difference.”
4. However, some people are more susceptible to SAD during the summer.
While it’s much less prevalent than the winter variety of SAD, some people do suffer from spring and summer SAD. Diagnosing and treating the disorder can be complicated, Solvason notes, mainly because conducting research on this specific type of depression is more challenging.
Experts theorize that warmer-weather SAD is aggravated by excessive heat and humidity, Rohan said. “Those triggers are really different than wintertime, which is brought on usually by lack of light and shorter days,” she explained. “It’s really a few people that we’re talking about as opposed to the wintertime SAD people can relate to on some level, but it does happen.”
5. Warm temperatures may put you in the mood.
There also appears to be a seasonal connection to an increase in human conception, according to Scientific American. In Europe, there seems to be a 10 percent above-average increase in births during the month of March, meaning the babies were conceived around June. Research also suggests that men's testosterone and women's hormones linked to ovulation spike to above-average levels in June, the publication reported.
6. You may exercise more during the spring.
What better way to exercise than outside in the sunshine? "Spring fever" seems to be an actual phenomenon, and one way people indulge in it is through a more active lifestyle, according to experts at the University of North Carolina. Exercise can lead to a boost in endorphins -- the same feel-good chemical that may come from warmer weather.
7. Warm weather may make you more inventive.
The University of Michigan study also found that being outdoors in enjoyable climates can improve memory and broaden cognitive style, which is linked to more creative thoughts.
“Being outside in pleasant weather really offers a way to reset your mindset,” said Matthew Keller, one of the study’s authors, when the research was released. “Everyone thinks weather affects mood, but the biggest tests of this theory ... found no relationship, so we went back and found there are two important variables: how much time you spend outside and what the season is. If you go from winter to spring and spend enough time outside, there’s a noticeable change.”
A previous version of this article appeared in April 2015.