Bedroom in a Tropical Night and Light | Creating a More Comfortable Environment for Hot Nights
Even at night, the temperature doesn't drop. It's too hot to sleep, and I wake up many times during the night.
According to the Japan Meteorological Agency, a night where the minimum temperature is 25°C or higher is called a "tropical night." In Japanese summers, especially from July to August, such nights have become increasingly common.
Let me state this clearly from the outset: lighting is not a tool to lower the room temperature. The primary countermeasures for tropical nights are air conditioning, bedding, and hydration.
Beyond that, organizing how you "use light" at night, which tends to be disrupted by the heat, can make tropical nights and mornings a little more comfortable. This article is about how to do that.
On tropical nights, the "number of times you wake up" increases.
On hot nights, sleep tends to be shallower, and you're more likely to wake up in the middle of the night.
You wake up to adjust the air conditioner. You wake up to drink water. You wake up sweating and change clothes. On tropical nights, there are more instances of "getting out of bed" than usual.
At such times, if you turn on all the room lights, the strong light will make you wide awake and also wake up your family. However, it's also unsafe to walk in complete darkness.
On tropical nights, when you're more active during the night, "minimal light" is essential.
For night activities, use handheld lighting.
Keep a small, easily accessible light by your bedside.
If it's a touch-sensitive light that turns on with a tap on the top, even a sleepy hand won't miss it. If it can be dimmed to a minimum brightness, you can see the air conditioner remote or a glass of water without becoming too awake. If it's cordless, you can even take it to the kitchen.
The Ministry of Health, Labour and Welfare's sleep guidelines also state that when going to the restroom at night, it's important to use indirect lighting or footlights to prevent falls and reduce the amount of light entering the eyes. Summer, when the number of times you wake up due to heat increases, is the season when this effort yields the most benefits.
For specific choices, please refer to What is a sleep light?
Use light that "looks cool."
Light doesn't change temperature, but it does change the impression of a room.
During the day and at dinner time, clear, whitish light (on the daylight white side) makes a space look cool. Conversely, some people find rich orange light, reminiscent of a kotatsu, to be stuffy on a summer night.
We recommend using cool-toned light until evening, and then switching to warm incandescent light just one hour before bedtime. This allows you to combine the effect of coolness with the principle of light before sleep. With a dimmable and color-tunable ceiling light, you can switch with just a remote control.
For the flow of light before sleep, please see How to adjust light an hour before sleep.
Summer mornings have too much light too early.
Along with tropical nights comes early summer sunrises.
In Tokyo in July, the sky starts to brighten as early as 4 AM. You finally managed to fall asleep despite the heat, only to be woken up by the morning light before 5 AM. Summer sleep problems stem from both the night's heat and the morning's light.
The solution is simple: control the morning light with blackout curtains. And when it's time to wake up, open the curtains and expose yourself to the morning light. "Block it while sleeping, bask in it when awake." This clear distinction maintains your summer rhythm.
A small checklist for summer nights
- Air conditioning, bedding, and hydration are the main players. Light acts as a supportive role.
- Keep a minimal, touch-sensitive light by your bedside.
- Don't turn on all the room lights during the night.
- Use cool tones until evening, then incandescent light for one hour before bed.
- Block early morning light with blackout curtains, and expose yourself to morning light when you wake up.
You don't need to do everything. If you often wake up during the night, start with the bedside light. If you wake up early in the morning, start with the curtains. Begin with the area closest to your concerns.
lipro's answer to summer nights
- Solar Sleep Light: Light for tropical nights. Top touch, 1-100% stepless dimming, cordless for free portability. 3000K incandescent color, RG0 certified.
- Solar Ceiling Light: Switch between "cool daylight white" and "incandescent color before sleep," 3000K-5000K, with a remote control. Ra97+, flicker-free.
Lighting doesn't lower the temperature. However, it plays a definite role in managing increased nighttime activity due to heat and the unique morning light of summer.
Summary: Cool down heat, organize light
Tropical night countermeasures are about division of labor.
Leave temperature and humidity to air conditioning and bedding. Keep water ready by the bedside. And for light, take on the two roles of "minimal light at night" and "controlling morning light."
The concept of nighttime light is discussed in Sleep and Light, and the combination of general room lighting and bedside lighting is organized in the article on proper usage. This summer, please add the "light" item to your night preparations.
References
- Japan Meteorological Agency "Terminology related to temperature" (definition of tropical night)
https://www.jma.go.jp/jma/kishou/know/yougo_hp/kion.html - Ministry of Health, Labour and Welfare "Sleep Guide 2023 for Health Promotion"
https://www.mhlw.go.jp/content/001305530.pdf - lipro "Solar Sleep Light"
https://jp.lipro.com/ja-jp/products/sleep-light-ja
