summer

Summer is one of the four temperate seasons, typically featuring warm to hot weather and the longest daylight hours of the year in many regions. The season is associated with active plant growth, outdoor recreation, and a peak in agricultural and tourism activity in temperate zones.

There are two common definitions of summer. Astronomical summer begins with the summer solstice, when the sun is at its highest declination and daylight is longest, and ends with the autumnal equinox. Meteorological summer uses calendar months: in the Northern Hemisphere, June through August; in the Southern Hemisphere, December through February.

Weather during summer varies by geography. In temperate zones it is characterized by higher average temperatures and longer days, with occasional heat waves and rainfall patterns shaped by local climate. In tropical regions, summers combine heat with seasonal rains; in deserts, summers are hot and dry. High-latitude areas may experience extended daylight or, near the arctic, rapid changes in light.

Summer supports ecological processes such as plant flowering and animal breeding. It also influences human activity, including agriculture, tourism, education, and energy demand for cooling. Ongoing climate change is increasing the frequency and intensity of extreme heat events in many regions, with wide-ranging impacts on health, ecosystems, and infrastructure.