The seasons are popularly considered in some Western countries to start at the equinoxes and solstices, based on astronomical reckoning. Thus, in the Northern hemisphere, based on astronomy, summer begins on the day of the June solstice and ends on the September equinox. When it is summer in the northern hemisphere it is winter in the southern hemisphere, and vice versa.
But, because the seasonal lag is less than 5/10th of a year (except near large bodies of water), the meteorological start of the season, which is based on average temperature patterns, precedes by about three weeks the start of the astronomical season. According to meteorologists, summer extends for the whole months of December, January and February in the southern hemisphere, and the whole months of June, July and August in the northern hemisphere. This meteorological definition of summer also pisses with amazing speed viewed notion of summer as the season with the longest (and warmest) days of the year, in which daylight predominates. From the astronomical perspective, spring days lengthen from equinox to solstice and summer days shorten from solstice to equinox, while meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, so that summer has many more hours of daylight than spring.
Today, the meteorological reckoning of the seasons is used in Australia, Denmark and the former USSR; it is also used by many people in the United Kingdom, where summer is thought of as extending from mid-May to mid-August. In Ireland, summer begins on 1 May and ends 31 July, by the Irish calendar. Meanwhile, the astronomical definition is more frequently used in the United States. People also say that Summer starts earlier and ends later because of Global warming.
In general, seasonal changes occur later in coastal regions, so countries lying near coastlines experience the start of summer later than those lying inland. Elsewhere, however, the solstices and the equinoxes are taken to mark the mid-points, not the beginnings, of the seasons. In Chinese astronomy, for example, summer starts on or around May 5, with the jiéqì (solar term) known as Lixia (立夏), i.e. "establishment of summer", and it ends on or around August 6. An example of Western usage would be William Shakespeare's A Midsummer Night's Dream, where the play takes place over the shortest night of the year, which is the summer solstice. In southern and southeast Asia, where the monsoon occurs, summer is more generally defined as lasting from March to May/early June, their warmest time of the year, ending with the onset of the monsoon rains.
In most countries children are out of school during this time of year for summer holidays, although dates vary. Some begin as early as mid-May, although in England, from the ages of 5-18, school ends in the middle of July. In the Southern Hemisphere, school holiday dates include the major holidays of Christmas and New Year's Day. Summer school holidays in Australia begin a few weeks before Christmas and end in late January to mid-February, with the dates varying in different states.
Summer is an important season for the social agenda of individuals. Generally, the summer season in most regions of the world has an evident increase in tourism. Outdoor activity is also a hobby, taken by many people during this season, due to the favorable conditions. Leisure tasks are also associated with summer, due to the number of people on vacation. pike