The “longest day” is the day with the most daylight (and the shortest night) in the Northern Hemisphere. It happens around the June (summer) solstice, typically between June 20–22, and most often near June 21.
This is driven by Earth’s axial tilt, not by daily weather changes.
When does the longest day happen?
- Northern Hemisphere: around the June solstice (usually near June 21).
- Day length varies by latitude: farther north means longer daylight.
Example (Istanbul – June 21, 2025)
In Istanbul on June 21, 2025:
- Sunrise is about 5:32 AM, sunset about 8:39 PM,
- Daylight lasts about 15 hours 7 minutes 40 seconds.
Why does it happen?
At the June solstice, the Northern Hemisphere is tilted toward the Sun:
- the Sun’s path is higher in the sky,
- it stays above the horizon longer,
- daylight increases while night shortens.
Is the longest day also the hottest day?
Not necessarily. The hottest period often comes later (July–August) due to seasonal heat lag.
Why aren’t the earliest sunrise and latest sunset on the solstice?
In most locations, the earliest sunrise occurs a few days before the solstice and the latest sunset a few days after it. This comes from how Earth’s orbit and tilt affect apparent solar time.