As the season changes, cool breezes and scattered autumn leaves of red, yellow and orange slowly give way to a winter wonderland. For many, winter is a joyous season, beginning with family gatherings and an extravagant dinner during Thanksgiving, then old St. Nick, and finally the countdown for the New Year to come. Yes—of all the seasons, winter is what adults and children alike both anticipate with great joy—and, often unknowingly, the blues.

Wintertime is perceived as a beautiful time with snow falling from the sky and Christmas lights illuminating the streets. There is more in the air than peace, love and joy, however. Also coming along for the ride are strong gusts of wind, pouring rain and foggy days, all of which have an amazingly negative affect on people’s mood and psyche.

Cody Wallace, who recently moved to San Francisco from the famously warm climate of San Diego, is trying to get out of the notoriously foggy Sunset district, where he is currently living. “Every time I wake up, I only see fog. It’s always foggy—it gets you down for sure.” His expression dropping at the mere mention of fog, Wallace says, “When it’s a gloomy day, you have less energy…(you) don’t want to do anything.”

According to the National Mental Health Association (NMHA), there is an actual term for the mood disorder caused by wintertime weather: Seasonal Affective Disorder (SAD). SAD causes depression in sufferers and is related to seasonal variations of light, which half a million people are affected by every winter.

Those who suffer from the disorder feel the effects between the months of September and April, with the strongest stage falling between December and February. Many people who suffer from SAD experience symptoms of tiredness, anxiety, mood changes, sleeping problems, lethargy, overeating, and even social and sexual problems.

“What people would experience from this disorder is depression that is correlated in this time of the month,” says Adam Burkes, a psychologist who teaches holistic health classes at SFSU. Burkes says SAD affects those who get limited sunlight the most.

“Everything calms down,” Jaram Kim says in a flat tone. “I don’t feel excited about anything. Even if there was something exciting going on, I don’t feel the excitement because I feel so calm.”

Having lived for sixteen years in Daly City, well-known for its foggy climate, Vladimir Fulgencio feels the doom of the gloom, even though there is a part of him that feels at home in the cold. “It affects what you wear, your outlook throughout the day,” he says. “When it’s cold, you don’t want to get up, you want to stay in bed and bundle up like a cocoon.”

“Sun puts you in a good mood, I always feel better when it’s sunny outside; it energizes you.” Smiling from ear to ear just thinking about the sun, Wallace says, “When it’s gloomy, you have less energy, don’t want to do anything compared to when it’s sunny. I feel like I’m wasting a day if I stay home.”

Burkes explains that in winter there is less sunlight throughout the day, causing less stimulation for the brain. This affects the hormone system, and as a result, emotions are hit negatively. NMHA states that during winter, a sleep-related hormone called melatonin, secreted by the pineal gland in the brain, is produced more often during the shorter and darker days of winter. This hormone is correlated to the cause of depression.

To reverse the effects of winter, Burkes says light therapy helps those who suffer from SAD. “A therapy that vastly improves the mood of people who suffer from SAD is Full Spectrum Light Therapy, which has all ten colors of the rainbow, better than any other kind of light.” The website Mayoclinic explains that light therapy or photo therapy mimic outdoor light given by the sun, which causes biochemical changes in the brain that lifts the mood.

A prescribed amount of light therapy, usually under a room full of white fluorescent lights, could vastly improve the sufferer’s mood. Burkes says most commercial bulbs are surface lights, which isn’t strong enough for the body to feel the light’s effects. “In order to treat SAD, you need a panel of light,” he says. “Undergoing light treatment would be easier for office workers though. They could sit under the lights while they’re working more than those workers whose jobs requires much more mobility.”

Burke says people who just feel down during winter, but are not diagnosed with SAD, could improve their funk by maintaining good health: getting enough sleep, eating a well-balanced diet, exercising regularly and even meditating.