What are the common misunderstandings about daylight hours and mood?
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Low mood in winter, struggling to get up, craving sweet things — the "winter depression" known in Scandinavia is talked about in Japan too, in the regions with the shortest daylight. If you have moved here from a sunnier country, the dark winters of the Sea of Japan coast can come as a surprise. Here we separate what belongs to medicine from what you can do with light in daily life.
The numbers
| Item | Details |
|---|---|
| Regional differences in sunshine (December normals) | Tokyo about 175 hours / Sapporo about 90 hours / Niigata about 60 hours / Kōchi about 200 hours (Japan Meteorological Agency) |
| Seasonal mood change | Depressive symptoms that start in autumn or winter and lift in spring are known in medicine as "seasonal affective disorder" (winter depression). More common at high latitudes and where sunshine is scarce |
| Light levels | Outdoor morning light is several thousand to over 10,000 lux, even under cloud. Indoor lighting is around 300–500 lux |
| Sleep Guide 2023 | Getting morning light after waking settles the body clock and helps you feel sleepy at night |
| When to see a doctor | Two weeks or more of near-daily low mood or loss of interest and pleasure, changes in sleep or appetite, disruption to daily life |
- Winter sunshine on the Sea of Japan side (Niigata, Akita, Toyama and others) is about a third of Tokyo's, and winter mood and sleep problems are a local talking point.
- Bright light therapy is carried out in medical settings; the "light alarm clocks" sold in shops are not medical devices (the light intensity and method of use differ).
[Verify] Check the sunshine normals with the Japan Meteorological Agency's "Historical weather data search", and the description of seasonal affective disorder against MHLW e-Health Net and the Japanese Society of Mood Disorders.
Misunderstanding 1｜Winter low mood is a matter of willpower
Changes in daylight, temperature and activity affect the body clock and mood — this is established in medicine. Tackling it as an environmental problem is the practical approach.
Misunderstanding 2｜Indoor lighting is enough
Indoor lighting is a few tens of times weaker than outdoor light. Eating breakfast by the window after getting up, or walking outside for 15–30 minutes, is the method shared among people living in Japan.
Misunderstanding 3｜If you live in a low-sunshine region, nothing can be done
By deliberately getting morning light, going out during the day, keeping up exercise and fixing a waking time, many people get through the winter.
Misunderstanding 4｜Craving sweets means a lack of grit
Increased craving for carbohydrates is a recognised feature of winter depression. Regular meals (do not skip breakfast) flatten the swings.
Misunderstanding 5｜It lifts in spring, so there is no need to see anyone
If you have low mood lasting two weeks or more, disruption to daily life, or thoughts of wanting to die, do not wait for the season: go to a doctor or a helpline (Yorisoi Hotline 0120-279-338; Kokoro no Kenkō Sōdan unified mental-health line 0570-064-556). This article is no substitute for a diagnosis.
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Sources
- Japan Meteorological Agency, "Historical weather data search" [過去の気象データ検索] (sunshine hours, normals)
https://www.data.jma.go.jp/stats/etrn/
- Ministry of Health, Labour and Welfare, *Sleep Guide for Health Promotion 2023* [健康づくりのための睡眠ガイド2023]
https://www.mhlw.go.jp/content/10904750/001181265.pdf
- Ministry of Health, Labour and Welfare, e-Health Net, "Depression" [うつ病] / Ministry of Health, Labour and Welfare, "Mamorou yo Kokoro" helpline directory [まもろうよ こころ]
https://www.mhlw.go.jp/mamorouyokokoro/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
About this article
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
This article is not meant to diagnose or manage any specific medical condition. If you are worried about your health, see a doctor rather than relying on your own judgement.
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