The hemisphere experiencing summer is tilted toward the Sun, increasing the Sun’s daily path across the sky and producing longer daylight hours.
Why days are longer
Earth’s axis is tilted about 23.5 degrees relative to its orbit, so when a hemisphere leans toward the Sun it receives sunlight for a longer portion of each rotation; the Sun rises earlier, sets later and follows a higher arc across the sky, lengthening daytime.
Local effects and evening light
In mid‑latitudes such as parts of Europe, this tilt can push sunset times well into the late evening, so around the summer solstice the Sun may set after 10 p.m. in many locations, producing long, bright evenings popular for outdoor activities.
Polar extremes and the midnight sun
The effect is strongest near the poles where, above the Arctic or Antarctic Circles, the Sun can remain continuously above the horizon for days or months around midsummer, a phenomenon known as the midnight sun observed in places like Norway and Sweden.
Practical note
Long summer daylight affects human activity, ecology and energy use: extended light hours shift work and recreation patterns, influence plant and animal behaviour and reduce evening heating needs in some regions, while also creating challenges for sleep in areas with very late sunsets.
Takeaway
Seasonal changes in day length are caused by Earth’s axial tilt; when your hemisphere tilts toward the Sun you get longer days, later sunsets and, at extreme latitudes, the continuous daylight of the midnight sun.