Why Summer Can Make You Feel Worse (Not Better)

Every June, the internet fills up with beach photos, rooftop plans, and some version of "summer is finally here." And if you find yourself dreading that — if the heat arriving feels like a weight rather than a relief, if you wake up exhausted when you're supposed to be energized — you are not broken, and you are not imagining it. Approximately 10 to 20 percent of people with recurrent depression experience a seasonal pattern to their mood,¹ and a recognized subset of those cases follow a summer rather than a winter cycle.

What Summer-Pattern SAD Actually Is (and Isn't)

Seasonal Affective Disorder is not a standalone diagnosis. Under DSM-5-TR, it is classified as a "with seasonal pattern" specifier applied to major depressive disorder or bipolar disorder — meaning a formal depressive episode that begins and ends at consistent times of year, has occurred for at least two consecutive years, and is not better explained by other stressors that happen to be seasonal.[2]

Most people have heard of SAD in the context of winter — the light-deprived months, the heavy blanket, the hibernation feeling. That is the more common form. But winter-onset is not the only form. The Cleveland Clinic, in their current clinical guidance on seasonal depression, explicitly recognizes summer-onset SAD as a distinct variant that begins in late spring or early summer and resolves in fall.[3] The University of Colorado Anschutz Medical Campus has also highlighted summer SAD in 2025 clinical commentary, with Stephanie Lehto, PsyD, an assistant professor of psychiatry, specifically noting the distinct symptom picture and the ways that disrupted summer routines worsen the presentation.[4]

The prevalence data is smaller than for winter SAD — a 2025 global meta-analysis of 24 studies and nearly 33,000 participants found a pooled general-population prevalence of 0.57% for summer-type SAD.[5] Among people who already experience seasonal depression, estimates suggest roughly 10% experience the summer-onset form.[6] So it is genuinely less common than winter SAD — but that also means it is significantly underrecognized, and people experiencing it are less likely to find their symptoms named in the literature they read or the conversations their doctors initiate.

The Symptoms Look Different From What You Expect

This is part of why summer depression is so confusing to live through. The cultural template for depression involves wanting to sleep all the time, eating too much, and hiding under covers. Winter SAD fits that template. Summer SAD often does not.

The symptom profile of summer-pattern SAD is, in clinical terms, the inverse.[7] Where winter SAD involves hypersomnia, summer SAD typically involves insomnia — difficulty falling asleep, staying asleep, waking early in the relentless brightness of a 5 AM sunrise. Where winter SAD involves increased appetite and carbohydrate cravings, summer SAD typically involves decreased appetite and weight loss. Where winter SAD involves lethargy, summer SAD often involves agitation, restlessness, and a kind of frantic flatness that does not look like the low mood people expect from depression.

That last piece is worth sitting with. Agitation can look like a lot of things that are not depression — anxiety, irritability, being difficult to be around. People with summer SAD sometimes do not recognize it as depression precisely because they are not lying in bed unable to move. They may be moving constantly, just without any of it feeling meaningful or good.

The contrast between the two presentations:

| | Summer SAD | Winter SAD | |---|---|---| | Sleep | Insomnia | Hypersomnia | | Appetite | Decreased | Increased, carb cravings | | Weight | Loss | Gain | | Energy / Mood tone | Agitated, restless | Lethargic, withdrawn | | Onset | Late spring / early summer | Fall / early winter | | Remission | Fall | Spring |

Why Heat Makes This Worse

There is now substantial research linking ambient heat to depression and other mental health outcomes — and for people already prone to summer mood changes, the heat is not neutral.

A January 2026 meta-analysis published in npj Mental Health Research (Nature), drawing on 28 studies and over 146,000 subjects, found that heat exposure was associated with an 18% higher risk of depression in children and adolescents, and a 14% higher risk for mental health hospitalizations overall.[8] This is not a small effect, and it is not limited to people who already have diagnoses.

For urban residents specifically, the picture is compounded by the urban heat island effect — the phenomenon in which dense city environments retain heat that rural and suburban areas can dissipate. A 2025 study drawing on the UK Biobank and 338,363 urban residents found that each standard deviation increase in urban heat island intensity was associated with an 8% higher risk of depressive disorder and a 6% higher risk of anxiety disorder.[9]

New York City in July and August is a specific kind of outdoor environment. The heat has nowhere to go. Apartment buildings that were warm in June become ovens by late July. Air conditioning shifts from comfort to survival. Sleep — already harder in summer SAD — becomes harder still in a hot apartment. And the sensory load of a heat-pressed city in peak summer is taxing in ways that most mental health writing does not acknowledge.

None of this is catastrophizing. It is a real physiological load layered on top of a mood that was already heading downward.

The Social Pressure Layer Nobody Talks About

Seasonal patterns do not happen in a vacuum. Summer depression happens inside a culture that has decided summer is the best time of year, that missing out on it is a personal failure, and that everyone around you is having the fun they were promised.

Research on social comparison and FoMO (fear of missing out) has sharpened considerably in recent years. A PLOS ONE meta-analysis published in September 2025, analyzing 32 studies and over 26,000 participants, found that FoMO showed the strongest correlation with depression of the five dimensions studied — with an effect size (r = 0.41) describing a real and meaningful relationship, not a weak association.[10] A separate 2025 study in Frontiers in Psychology found that social comparison was the strongest predictor of FoMO (beta = 0.43), with upward comparison — measuring yourself against people who appear to be doing better, having more fun, living bigger — driving the effect most powerfully.[11]

Summer is structurally engineered for upward social comparison. Every beach photo, every rooftop party announcement, every "best summer ever" caption is a data point against which someone already in a low mood is measuring their own experience. When the culture's expectation and your internal reality are this far apart, the gap itself becomes something you carry.

This is not about weak character or ingratitude. It is about what happens when a mood state collides with a cultural season that has very strong expectations attached to it. The expectation that you should feel great does not help you feel great. It often makes feeling bad feel worse.

Structure Collapse Is Its Own Problem

One of the underappreciated contributors to summer depression — particularly for adults with children, or for adults who rely on routine as a form of regulation — is the way summer dismantles structure.

School ends. Schedules stop. The reliable cadence of Monday through Friday, the rhythm of the school drop-off, the meeting schedule, the predictable commute — all of it either disappears or becomes irregular. For many people, that structure was not just a logistical convenience. It was doing real regulatory work.

Structure regulates sleep. It regulates appetite. It creates natural exposures to daylight, movement, and social contact at predictable times. When structure collapses in June, some people barely notice. Others feel it as a kind of internal freefall — not dramatic enough to name, but real enough to worsen a mood that was already fragile.

Lehto at CU Anschutz noted exactly this in 2025 commentary: disrupted routines — irregular eating, irregular sleep, the absence of the natural rhythm that the school year provides — worsen the summer depression picture, even for people who do not immediately make that connection.[4]

What Actually Helps

The good news — and there is real good news here — is that summer-pattern SAD responds to treatment. The interventions are not the same as for winter SAD. Light therapy, which works well for winter SAD, is not indicated for the summer form and can worsen it. But there are real options.

Cool, dark sleep environment. Sleep disruption drives a significant portion of the symptom picture in summer SAD. A room that is genuinely dark and cool — blackout curtains, air conditioning where possible, keeping the bedroom separate from screens and heat — addresses a core mechanism, not just a preference.

Maintain whatever routine you can. Even a reduced version of routine matters. If you cannot maintain the full structure of the school-year schedule, building anchors — a consistent wake time, a consistent meal time, a consistent time to move — gives your nervous system predictable signals in a season that otherwise removes them.

Recognize the comparison cycle for what it is. Knowing that the social comparison research is real and that the gap between the summer you see online and the summer you are living is a manufactured comparison — not evidence of failure — does not eliminate the feeling. But it can interrupt the cycle where the gap becomes evidence that something is fundamentally wrong with you.

Work with a therapist who understands seasonal patterns. Cognitive behavioral therapy has a strong evidence base for seasonal depression across both presentations. The medication options for summer SAD also differ from winter SAD, and a prescriber who understands the summer variant approaches it differently. If you have noticed your mood following a consistent summer pattern over multiple years, that information is clinically useful and worth naming explicitly when you describe what is happening.

Working with a therapist does not change the weather or the calendar. But it can help you understand your own pattern — when it starts, what makes it worse, what has helped before — and build around it with enough lead time to actually do some good. If you want to talk through what that might look like, a free call is a reasonable place to start.

A Note on New York City Specifically

New York summer is its own thing. The heat index in August is not what it says on the weather app. The subway platforms have their own climate. Apartments in older buildings were not designed for a world where July averages keep climbing. Outdoor space — the park, the waterfront, the neighborhood you want to walk through — becomes functionally inaccessible between noon and six PM for weeks at a time.

For people already prone to summer depression, this is not just unpleasant. It is a real physiological load. The urban heat island research described above was conducted in UK urban environments — not New York City specifically — but the mechanism is the same, and NYC ranks among the most intense urban heat islands in the country during peak summer.

If your summers feel genuinely worse than your summers elsewhere, or worse than your winters in the same city, that is not a soft preference. It is data worth taking seriously.