🌍 What is OhayoWorld?

OhayoWorld is a live world map that shows where it is currently daytime, twilight, or night across the globe. It updates every few seconds, letting you watch the day and night boundary travel around the Earth in real time.

📍 City Markers

• Daytime The sun is above the horizon. It is daylight.
• Dawn or dusk The sun is just rising or setting — the golden hour.
• Nighttime The sun is below the horizon. City lights are on.
• Your location Appears when you tap the location button.

🌑 The Shaded Zones

• Civil twilight The lighter shaded band. The sun has just set (or is about to rise) and is less than 6° below the horizon. The sky still has a faint glow — you can see without artificial light. This is the "golden hour" zone.
• Civil night The darker shaded area. The sun is more than 6° below the horizon. It is truly dark outside.
• Daytime The unshaded area. The sun is above the horizon.

🌐 The Two Special Markers

• Subsolar point The pulsing sun marker shows the spot on Earth where the sun is exactly overhead right now. It drifts westward at about 1,670 km/h — Earth's equatorial rotation speed — and oscillates between the Tropics of Cancer and Capricorn over the year as Earth orbits the sun.
• 🌒
  Sublunar point The moon-phase emoji shows the spot on Earth where the moon is exactly overhead at this moment. The emoji updates to reflect the current lunar phase: 🌑 new moon, 🌕 full moon, and all stages in between.

⏱️ Why Sunrise Times Don't Match the Map Edge

The shaded zone on the map is a geometric calculation — its outer edge marks exactly where the sun's center sits at the mathematical horizon. But city sunrise and sunset times are slightly earlier and later, for two reasons:

• 🌡️
  Atmospheric refraction The atmosphere bends sunlight, making the sun visible about 4–5 minutes before it geometrically clears the horizon. At the moment of visible sunrise, the sun is actually still just below the geometric horizon.
• 🔆
  Size of the solar disk Sunrise is defined as when the top edge of the sun's disk first appears above the horizon, not its center — adding another 1–2 minutes.

Together, these effects mean a city sees sunrise about 6 minutes before the map's edge geometrically reaches it, and sunset about 6 minutes after it passes. Near the poles, where the sun crosses the horizon at a very shallow angle, this gap can be even larger.

🃏 The Cards at the Bottom

These cards show cities that are about to experience a sunrise, solar noon, or sunset, with a live countdown. They update automatically as the day travels around the world — and a city appears only once, even if its status changes.

☀️ Why "OhayoWorld"?

"Ohayo" (おはよう) means "good morning" in Japanese — a greeting for the start of a new day. Somewhere on Earth, it is always morning.