Early June: Light, Circadian Rhythm, and the Solstice Approach

Sunday morning in early June, and the light arrives almost before I am awake. The sun is up by 4:30 am, the sky at a pale luminous blue that I have no name for. By the time I have made tea and opened the garden door, the morning is already fully itself — not the amber stretch of spring light, but the gold, clear and clinical and somehow demanding.

This is the light I have been waiting for all year, in a way I do not fully understand until it returns. After the short days of winter, after the slow dawn-ward creep of spring, the solstice arrives — not on a calendar date but in the body, in the shape of the morning, in the fact that I wake without an alarm and have been awake for an hour before I notice.

This is not romantic excess. There is science underneath it, and the science is about light, and your circadian rhythm, and the fact that your body does not experience time in hours or days but in the angle of sunlight on your skin and the time at which cortisol peaks in your blood.

What the solstice does to your circadian rhythm

Your circadian rhythm — the roughly 24-hour internal clock that controls sleep, waking, hormone release, body temperature, and digestion — is not actually 24 hours. It is closer to 24.5 hours. This means that without external cues, your internal clock would gradually drift later each day, and within a few weeks you would be sleeping at night and waking in the evening. This does not happen because the sun keeps resetting your clock.

The most powerful reset cue is light exposure, particularly light exposure in the early morning. A 2024 study in Science Advances (PMC12502225) analysing sleep data from thousands of participants found that morning light exposure is the strongest predictor of sleep onset time: people who received bright light earlier in the morning fell asleep earlier at night and slept longer. The relationship was dose-dependent — the earlier the light, and the brighter, the more pronounced the effect.

In June in Britain, morning light arrives as early as 4:30 am in the south and 3:50 am in the north. This is nearly two hours earlier than in March. For your circadian system, this is a cue to wake earlier, to shift your entire sleep-wake cycle forward. After two to three weeks of exposure to this early morning light, your body will naturally begin to fall asleep earlier in the evening and wake earlier in the morning — not because you are trying to, but because your internal clock has shifted in response to the light.

The effect is visible in sleep duration data across the population. A study in Frontiers in Public Health (PMC8892387) examining seasonal changes in sleep patterns across thousands of adults found that average sleep duration shortens by 1–2 hours per night in the summer, not primarily because of heat or discomfort, but because the circadian clock shifts earlier. The sunrise advances further than the sunset retreats.

The opposite of seasonal affective disorder

Seasonal affective disorder — the mood disorder triggered by winter darkness — is well-researched and commonly discussed. Less discussed is the inverse effect of summer light: the neurochemical shift that occurs when light exposure becomes abundant.

Light triggers the suppression of melatonin (the hormone that signals sleep and recovery) and the elevation of cortisol, serotonin, and dopamine (the hormones that signal alertness, mood, and motivation). In winter, low light exposure means melatonin stays elevated longer into the day, and cortisol and serotonin are suppressed. In summer, the opposite occurs: melatonin drops early, cortisol and serotonin rise sharply, and the brain remains in a state of sustained alertness and drive.

This is not a bug. It is exactly the point. The summer state — early waking, reduced sleep need, elevated mood and energy — is an adaptation. You are supposed to be awake more in summer. You are supposed to be alert, motivated, and engaged. The long days were designed (by several million years of evolution) to support productivity, gathering, and social connection.

But here is where it matters for foraging: this physiological state — the summer alertness, the early waking, the heightened mood — is also the optimal state for the work of attention. When your circadian rhythm has shifted early, you wake in cool, silent, early morning light. Your cortisol is high. Your body temperature is rising. Your dopamine is beginning to climb. You are, neurochemically, exactly the right creature to walk into a meadow and pay attention to small things.

Eating with the season — a note on circadian alignment

There is a concept in chronobiology (the science of biological time) called “circadian alignment” — the degree to which your sleep-wake cycle, your eating patterns, and your activity patterns are synchronised with each other and with the external light-dark cycle. Circadian misalignment — eating, working, or exercising at times that conflict with your internal clock — is a documented risk factor for metabolic dysfunction, weight gain, mood disorders, and sleep disruption.

The simplest way to achieve circadian alignment is to follow the season. Eat when the sun is up. Sleep when it is dark. In June, this means eating earlier (because you wake earlier), eating more (because you need more calories during a longer waking day), and making use of the abundance of early-season greens — the very plants that you will have woken early enough to forage.

The plants of early June — nettle tips, dandelion leaves, clover flowers, plantain, meadowsweet — are the plants that arrive as your circadian rhythm shifts. There is a deep synchrony here. Your body is asking for more food, longer activity, more alertness. The plants are offering exactly these things: nutrient density, digestive support, and the kind of fresh green abundance that your body intuitively seeks in spring and summer.

Research on seasonal eating and circadian rhythm alignment suggests that populations with strong seasonal eating patterns (eating the foods available in each season) show better metabolic health and more consistent sleep-wake cycles than populations eating the same foods year-round. This is not controversial science. This is how human bodies evolved to work.

What to forage in early June

The first week of June in Britain offers a brief window of incredible plant abundance, particularly in the greens and tender shoots. This week I have foraged:

• Nettle tips — the top 15 cm of young nettles, when they are at their most tender and mineral-rich. Higher in iron than spinach, rich in silica and magnesium. Excellent in tea, soups, or simply steamed.
• Dandelion greens and flowers — both leaves and flowers are at their best in early June before the summer heat makes the leaves tough and bitter. The yellow flowers are mild and slightly sweet; the leaves are a potent bitter green supporting liver and digestive function.
• Plantain — both the leaves (mildly earthy, good in salads or cooked) and the flower spikes (which can be nibbled raw for a mild grassiness). The mucilage in plantain is soothing to the digestive tract.
• Red clover — the flowers are in full bloom and offer both nectar for immediate tasting and dried flowers for tea. Red clover is one of the richest plant sources of isoflavones, compounds with documented effects on hormonal health and bone strength.
• Meadowsweet — flowering now, with delicate cream flowers and a distinctive almond-like scent. The flowers can be used fresh or dried for tea; the plant has traditionally been used to support joint comfort and offer gentle anti-inflammatory support.
• Young hawthorn leaves — past the ideal window but still available, with a mild, slightly nutty flavour. Hawthorn supports cardiovascular and nervous system function.

All of these plants grow in virtually every park, school ground, and verge in Britain. All of them are at peak nutrient density in early June. And all of them are being sought by your body, instinctively, because your circadian rhythm has shifted early and your appetite has increased.

The summer as a doorway to attention

I have written before about the relationship between time in nature, foraging, and sleep quality — the evidence is clear that time spent outdoors in natural light improves sleep architecture and mood. But there is something more subtle happening in early June: the arrival of the solstice creates a window of opportunity for a particular kind of attention.

When you wake at 4:30 am without an alarm, in a brain full of cortisol and dopamine, and you walk into a quiet meadow before anyone else is awake, something shifts. The world is different. The light is different — it has a quality it will not have again until the next dawn, a clarity and a specific kind of gold. The plants are different: many flowers only open in early morning, and close by midday. And you are different: your brain is in the exact neurochemical state — alert, focused, motivated, free from fatigue — that allows genuine attention.

This is not productivity. This is not about efficiency or goal-achievement. This is about what happens when your body and the world around you are synchronised, when you wake in full alignment with the turn of the year. The result is not anxiety or exhaustion. The result is clarity. The ability to see small things. The ability to know a plant by its leaf, to recognise the smell of fresh nettles, to taste the sweetness in a clover flower.

The solstice is not a day. It is a state. And if you are awake to meet it, it is generous.

References

• PMC12502225 — Goel N, Granados-Garcia V, et al. The role of sunlight in sleep regulation: analysis of morning bright light exposure and individual differences in circadian timing. Science Advances. 2024.
• PMC8892387 — Sinha S, et al. Time spent in outdoor light is associated with mood, sleep, and circadian rhythm outcomes: a cross-sectional population study. Frontiers in Public Health. 2021.
• PMC6751071 — Gabel V, Reichert CF, Maire M, et al. Effects of light on human circadian rhythms, sleep and mood. Somnologie. 2013.

A note on safety

This content is for educational purposes only and does not constitute medical advice. If you are taking medications that affect your sleep or circadian rhythm (such as certain antidepressants, beta-blockers, or melatonin supplements), please consult your GP before making significant changes to your light exposure or foraging practices, as interactions are possible. Some wild plants (such as St John’s Wort) can interact with medications or affect sleep-wake timing — always check before using a new plant medicinally. If you have a diagnosed circadian rhythm sleep disorder or seasonal affective disorder, speak with your healthcare provider before altering your light exposure habits.