For some, a cloudy day has the power to turn a smile into a frown. A lack of sunshine may make one feel like a half-charged battery, and if rain comes pelting into the mix, drops sound off like a depressing drum beat.

As some nations have plowed through a recent polar vortex that set records across the world, many are wondering whether or not weather affects our moods. Could specific weather patterns kick us into seasonal depression, or even make us aggressive? Could clouds make us want to isolate from others—or could the way we feel be a pure coincidence stemming from other factors in our lives?

Many of us have felt “off” during questionable weather at some point in our lives. Let’s explore how certain weather may make us feel down in the dumps.

Light, the Brain, and Weather’s Influence on Serotonin

Our brains are heavily influenced by light. Light (and the absence of it) regulates our melatonin production, which makes us sleep when it’s dark and wake when the sun pokes through our blinds. With bad weather comes one distinct element: an absence of light.

A 2008 study published in the journal Emotion took a multi-pronged approach in exploring six weather parameters and their effects on both mood and tiredness. The results were a compelling tale—temperature, the power and force of the wind, and the amount of sunlight all affected moods.

While factors will affect some more than others, sunlight is a key find here—how much sunlight you’re exposing yourself to likely affects your disposition. A recent study in Australia found that people had higher levels of serotonin on bright, sunny days rather than darker, cloudier ones—no matter how hot or cold the weather was.

This brings us to people working night shifts. Those that disrupt their systems by sleeping during the day and being awake at night—under artificial light—are agitating many functions that make for a happy, healthy body. Sleeping during the day, when the sun is out, chips away essential chemicals that regulate our weight, energy levels, mood, and much more.

Even people that use tanning beds were found to have triggered happiness levers, which has even led to tanning bed dependency in some.

Seasonal Affective Disorder

Do you feel especially sad when winter months come marching in? If so, you may have a case of SAD.

A serious case of winter doldrums, SAD affects 4 to 5 percent of the population, while up to 20 percent of people across the globe experience mild forms of SAD. Seasonal depression is more common the farther north you are—you’re seven times more likely to have seasonal affective disorder if you live in Washington than if you live in Florida.

Symptoms of SAD range across the spectrum, but generally include a drop in energy level, irritability, increased sensitivity, oversleeping, avoidance of social situations, and weight gain. Those with SAD tend to experience these or similar symptoms during the same months—winter. There are even rare cases of summertime SAD, which also has to do with the way light affects the brains of certain people.

Light therapy has been hailed as a saving grace for seasonal depression. Especially useful for those living in areas with wintertime darkness, light therapy can be utilized with special light boxes or by wearing light visors and is effective when used approximately 30 minutes per day.

Different Weather Patterns and Your Mood

Different weather patterns have been shown to dredge up a legion of feelings. Let’s explore how particular forms of weather tend to affect people.

Rain and Sadness

Rain does have the power to bring your spirit down. Rain blocks sunlight, which is a mood-boosting element that can make you feel chipper throughout your day.

Psychiatrist Julia Sampton at NYC’s Manhattan Neuropsychiatric has some uplifting advice for rainy days; “I encourage people to really try to make sure they walk outside, even when it’s cold and rainy,” she says. “Even though it might not seem that light out, you’ll still get some exposure to UV rays, which can help regulate your body’s circadian rhythm and boost your mood.”

Extreme Weather and Altruism

Cases of traumatic incidents, loss of life, and difficulties posed by severe weather can be terrifying, but as a whole, extreme weather tends to surface the good in people. This means coming together in times of hardship, offering a hand to a neighbor, or helping strangers in need.

Time Healthland wrote the following: "Although there’s a mentality that disasters provoke frenzied selfishness and brutal survival-of-the-fittest competition, the reality is that people coping with crises are actually quite altruistic."

Heat and Violent Crimes

Researchers from UC Berkeley got into the nuts and bolts of previous studies on U.S. crime rates and found a disconcerting phenomenon—when the heat rises, with it comes a flurry of crime. The case is the same with extreme rainfall, too. Murders take an upward trend in cities like Chicago during transition months, when spring starts to heat up into summer months.

Temperate Weather and Overall Happiness

One study published in Nature reports that those that live in temperate climates—where it’s not too hot in the summer and not terribly cold in the winter—tend to, on average, experience higher levels of happiness.

Researchers found that those living in more temperate climates tended to score higher in areas of conscientiousness, agreeableness, and emotional stability. They even found the perfect temperature for optimal personality traits—22 degrees Celsius (or 71.6 degrees Fahrenheit).

Weather and You

If you’ve had a few off days because of the weather, don’t pack up and move to Hawaii just yet—some of the studies mentioned found that the gap between weather and a person’s emotions was rather small. But if you’re someone that’s greatly affected by weather, it may be time to walk outside and get some sunshine—even if it’s hiding behind a few clouds.