Here's why:

* The Earth's Tilt: The Earth is tilted on its axis at approximately 23.5 degrees. This tilt is the primary reason we have seasons.

* Summer Solstice: During the June solstice (around June 21st), the Northern Hemisphere is tilted towards the Sun. This is because the North Pole is pointed most directly at the Sun at this time. This means that the Northern Hemisphere receives the most direct sunlight and experiences the longest period of daylight.

So, while the Southern Hemisphere experiences winter in June, the Northern Hemisphere experiences summer.