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Feeling SAD in summer? Yes, it's a thing.

A pensive woman leans against the foot of a bed.

April 28, 2025—For some people, the brighter days of spring and summer can mean darker moods. The cause: a rare, summer-pattern form of seasonal affective disorder (SAD).

SAD is a recurrent form of depression that is linked to seasonal changes. Most people with the condition experience symptoms from fall or early winter through spring. The condition is triggered by winter's shorter days and reduced sunlight.

But for people with summer-pattern SAD, symptoms start in spring—as days are lengthening—and continue through fall.

Some summer-pattern SAD symptoms are the same as for the winter version. These include:

Sadness.
Hopelessness.
Pessimism.
Guilt.
Loss of interest or pleasure in hobbies or activities.
Fatigue and lack of energy.
Difficulty concentrating, remembering or making decisions.
Sleep changes.
Thoughts of suicide or suicide attempts.

But the symptoms of summertime SAD also can include:

Insomnia.
Poor appetite and weight loss.
Restlessness.
Irritability and anxiety.
Agitation.

What causes summer-pattern SAD

Researchers are still working to discover more about how seasonal changes could cause SAD symptoms in summer. It may be that longer hours of daylight and hot weather interfere with nightly sleep quality.

Another possible explanation connects summer-pattern SAD to changes in neurotransmitters. Mood-regulating neurotransmitters, like serotonin, dopamine and norepinephrine, help the body regulate its temperature. When they aren't balanced, people may be more prone to depression and more affected by heat and humidity. Together, these things may trigger depressive symptoms in the summer.

What you can do

If you're experiencing depression, ask your doctor or mental health care provider for help. That's good advice at any time of the year.

If you've noticed a pattern in the way your symptoms come and go, make sure to share that with your provider. If you've had symptoms of depression that last for months during summer over at least two years, you may have summer-pattern SAD.

Together, you and your provider can develop a personalized treatment plan to prevent summertime SAD episodes—and make your days feel brighter again.

You're not alone

If you're living with SAD or another mental health condition, your primary care provider can help you get the support and treatment you need. Not sure how to start the conversation? These tips can help.

Sources

American Medical Association. "What Doctors Wish Patients Knew About Seasonal Affective Disorder." https://www.ama-assn.org/delivering-care/public-health/what-doctors-wish-patients-knew-about-seasonal-affective-disorder.
American Psychological Association. "How Heat Affects the Mind." http://www.apa.org/monitor/2024/06/heat-affects-mental-health.
FamilyDoctor.org. "What Is Seasonal Affective Disorder?" https://familydoctor.org/condition/seasonal-affective-disorder.
HelpGuide. "Seasonal Affective Disorder (SAD): Symptoms, Causes, and Treatment of Seasonal Depression." https://www.helpguide.org/mental-health/depression/seasonal-affective-disorder-sad.
National Institute of Mental Health. "Seasonal Affective Disorder." https://www.nimh.nih.gov/sites/default/files/documents/health/publications/seasonal-affective-disorder/seasonal-affective-disorder-508.pdf.