Summer

Summer is one of the four seasons of the year. In the Northern Hemisphere, it generally extends from the June solstice to the September equinox, while in the Southern Hemisphere it occurs during the opposite part of the year. The exact dates of these astronomical events vary slightly from one year to another. Summer begins, in the astronomical sense, with the June solstice, when the Northern Hemisphere is tilted toward the Sun and receives more direct sunlight than during the other seasons.

This does not happen because Earth is much closer to the Sun in summer. In fact, Earth's distance from the Sun changes during its orbit, but the seasons are mainly caused by the tilt of Earth's axis, which is about 23.4 degrees. The combination of this tilt and Earth's movement around the Sun changes the angle and duration of sunlight received in each hemisphere.

During summer, longer days and a higher Sun generally provide more solar energy to the ground, although the actual weather depends strongly on location, altitude, oceans, winds, and other climate factors. In many regions, plants grow actively and animals adjust their behavior to the warmer and brighter conditions. Some species reproduce or raise their young during this period, while others reduce activity during the hottest hours.

Summer is also an important season for agriculture, since temperature, rainfall, and daylight influence the growth and harvesting of many crops. The season is not equally hot everywhere: near the poles, temperatures can remain relatively low, while some inland or subtropical regions can experience intense heat. Summer therefore results from the seasonal distribution of sunlight caused mainly by Earth's axial tilt, while local climate determines how that season is actually experienced.