|Northern temperate zone|
|Astronomical season||21 June – 23 September|
|Meteorological season||1 June – 31 August|
|Solar (Celtic) season||1 May – 31 July|
|Southern temperate zone|
|Astronomical season||22 December – 21 March|
|Meteorological season||1 December – 28/29 February|
|Solar (Celtic) season||1 November – 31 January|
| Summer |
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Summer is the hottest of the four temperate seasons, occurring after spring and before autumn. At or centred on the summer solstice, the earliest sunrise and latest sunset occurs, daylight hours are longest and dark hours are shortest, with day length decreasing as the season progresses after the solstice. The date of the beginning of summer varies according to climate, tradition, and culture. When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere, and vice versa.
From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons,but sometimes astronomical summer is defined as starting at the solstice, the time of maximal insolation, often identified with the 21st day of June or December. By solar reckoning, summer instead starts on May Day and the summer solstice is Midsummer. A variable seasonal lag means that the meteorological centre of the season, which is based on average temperature patterns, occurs several weeks after the time of maximal insolation.
The meteorological convention is to define summer as comprising the months of June, July, and August in the northern hemisphere and the months of December, January, and February in the southern hemisphere.Under meteorological definitions, all seasons are arbitrarily set to start at the beginning of a calendar month and end at the end of a month. This meteorological definition of summer also aligns with the commonly viewed notion of summer as the season with the longest (and warmest) days of the year, in which daylight predominates.
The meteorological reckoning of seasons is used in countries including Australia, New Zealand, Austria, Denmark, Russia and Japan. It is also used by many people in the United Kingdom and Canada. In Ireland, the summer months according to the national meteorological service, Met Éireann, are June, July and August. By the Irish calendar, summer begins on 1 May (Beltane) and ends on 31 July (Lughnasadh).
Days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring. Reckoning by hours of daylight alone, summer solstice marks the midpoint, not the beginning, of the seasons. Midsummer takes place over the shortest night of the year, which is the summer solstice, or on a nearby date that varies with tradition.
Where a seasonal lag of half a season or more is common, reckoning based on astronomical markers is shifted half a season.By this method, in North America, summer is the period from the summer solstice (usually 20 or 21 June in the Northern Hemisphere) to the autumn equinox.
Reckoning by cultural festivals, the summer season in the United States is traditionally regarded as beginning on Memorial Day weekend (the last weekend in May) and ending on Labor Day (the first Monday in September), more closely in line with the meteorological definition for the parts of the country that have four-season weather. The similar Canadian tradition starts summer on Victoria Day one week prior (although summer conditions vary widely across Canada's expansive territory) and ends, as in the United States, on Labour Day.
In some Southern Hemisphere countries such as Brazil, Argentina, South Africa, Australia and New Zealand, summer is associated with the Christmas and New Year holidays. Many families take extended holidays for two or three weeks or longer during summer.
In Chinese astronomy, summer starts on or around 5 May, with the jiéqì (solar term) known as lìxià (立夏), i.e. "establishment of summer", and it ends on or around 6 August.
In southern and southeast Asia, where the monsoon occurs, summer is more generally defined as lasting from March, April, May and June, the warmest time of the year, ending with the onset of the monsoon rains.[ citation needed ]
Because the temperature lag is shorter in the oceanic temperate southern hemisphere,most countries in this region use the meteorological definition with summer starting on 1 December and ending on the last day of February.
Summer is traditionally associated with hot or warm weather. In Mediterranean climates, it is also associated with dry weather, while in other places (particularly in Eastern Asia because of the monsoon) it is associated with rainy weather. The wet season is the main period of vegetation growth within the savanna climate regime.Where the wet season is associated with a seasonal shift in the prevailing winds, it is known as a monsoon.
In the northern Atlantic Ocean, a distinct tropical cyclone season occurs from 1 June to 30 November.The statistical peak of the Atlantic hurricane season is 10 September. The Northeast Pacific Ocean has a broader period of activity, but in a similar timeframe to the Atlantic. The Northwest Pacific sees tropical cyclones year-round, with a minimum in February and March and a peak in early September. In the North Indian basin, storms are most common from April to December, with peaks in May and November. In the Southern Hemisphere, the tropical cyclone season runs from the start of November until the end of April with peaks in mid-February to early March.
Thunderstorm season in the United States and Canada runs in the spring through summer but sometimes can run as late as October or even November in the fall. These storms can produce hail, strong winds and tornadoes, usually during the afternoon and evening.
Schools and universities typically have a summer break to take advantage of the warmer weather and longer days. In almost all countries, children are out of school during this time of year for summer break, although dates vary. Many families will take holidays for a week or two over summer, particularly in Southern Hemisphere Western countries with statutory Christmas and New Year holidays.
In the United States, public schools usually end in late May in Memorial Day weekend, while colleges finish in early May. Public school traditionally resumes near Labor Day, while higher institutions often resume in mid-August.
In England and Wales, school ends in mid-July and resumes again in early September. In Scotland, the summer holiday begins in late June and ends in mid-to late-August. Similarly, in Canada the summer holiday starts on the last or second-last Friday in June and ends in late August or on the first Tuesday of September, with the exception of when that date falls before Labour Day, in which case, ends on the second Tuesday of the month. In Russia the summer holiday begins at the end of May and ends on 31 August.
In the Southern Hemisphere, school summer holiday dates include the major holidays of Christmas and New Year's Day. School summer holidays in Australia, New Zealand and South Africa begin in early December and end in early February, with dates varying between states. In South Africa, the new school year usually starts during the second week of January, thus aligning the academic year with the Calendar year. In India, school ends in late April and resumes in early or mid-June. In Cameroon and Nigeria, schools usually finish for summer vacation in mid-July and resume in the later weeks of September or the first week of October.
A wide range of public holidays fall during summer, including:
People generally take advantage of the high temperatures by spending more time outdoors during summer. Activities such as travelling to the beach and picnics occur during the summer months. Sports including cricket, association football (soccer), horse racing, basketball, American football, volleyball, skateboarding, baseball, softball, tennis and golf are played.
Water sports also occur. These include water skiing, wakeboarding, swimming, surfing, tubing and water polo. The modern Olympics have been held during the summer months every four years since 1896. The 2000 Summer Olympics, in Sydney, were held in spring and the 2016 Summer Olympics, in Rio de Janeiro, were held in winter.
In the United States, many television shows made for children are released during the summer, as children are off school.
Conversely, the music and film industries generally experience higher returns during the summer than other times of the year and market their summer hits accordingly. Summer is popular for animated movies to be released theatrically in movie theaters.[ citation needed ]
With many schools closed, especially in Western countries, travel and vacationing tend to peak during the summer. Teenagers and university students often take summer jobs, and business activity for the recreation, tourism, restaurant, and retail industries reach their peak.
Autumn, also known as Fall in American English and Canadian English, is one of the four temperate seasons. Outside the tropics, autumn marks the transition from summer to winter, in September or March. Autumn is the season when the duration of daylight becomes noticeably shorter and the temperature cools considerably. Day length decreases and night length increases as the season progresses until the Winter Solstice in December and June. One of its main features in temperate climates is the striking change in colour for the leaves of deciduous trees as they prepare to shed.
Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultures define different dates as the start of winter, and some use a definition based on weather.
Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of the term varies according to local climate, cultures and customs. When it is spring in the Northern Hemisphere, it is autumn in the Southern Hemisphere and vice versa. At the spring equinox, days and nights are approximately twelve hours long, with daytime length increasing and nighttime length decreasing as the season progresses until the Summer Solstice in June and December.
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather, while high-pressure areas are associated with lighter winds and clear skies. Winds circle anti-clockwise around lows in the northern hemisphere, and clockwise in the southern hemisphere, due to opposing Coriolis forces. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the atmosphere (aloft). The formation process of a low-pressure area is known as cyclogenesis. In meteorology, atmospheric divergence aloft occurs in two kinds of places:
Seasonal lag is the phenomenon whereby the date of maximum average air temperature at a geographical location on a planet is delayed until some time after the date of maximum insolation. This also applies to the minimum temperature being delayed until some time after the date of minimum insolation.
The 2005 North Indian Ocean cyclone season was destructive and deadly to southern India, despite the weak storms. The basin covers the Indian Ocean north of the equator as well as inland areas, sub-divided by the Arabian Sea and the Bay of Bengal. Although the season began early with two systems in January, the bulk of activity was confined from September to December. The official India Meteorological Department tracked 12 depressions in the basin, and the unofficial Joint Typhoon Warning Center (JTWC) monitored two additional storms. Three systems intensified into a cyclonic storm, which have sustained winds of at least 63 km/h (39 mph), at which point the IMD named them.
The 1996 Pacific typhoon season has no official bounds; it ran year-round in 1996, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.
The 1987 Pacific typhoon season has no official bounds; it ran year-round in 1987, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean. Tropical storms formed in the entire west pacific basin were assigned a name by the Joint Typhoon Warning Center. Tropical depressions that enter or form in the Philippine area of responsibility are assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA. This can often result in the same storm having two names.
The 1980 Pacific typhoon season has no official bounds; it ran year-round in 1980, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean. Tropical storms which formed in the entire west Pacific basin were assigned a name by the Joint Typhoon Warning Center. Tropical depressions that enter or form in the Philippine area of responsibility are assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA. This can often result in the same storm having two names.
The monsoon trough is a portion of the Intertropical Convergence Zone in the Western Pacific, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and northern hemispheres.
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.
The summer solstice, also called the estival solstice or midsummer, occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere. For that hemisphere, the summer solstice is the day with the longest period of daylight and shortest night of the year, when the Sun is at its highest position in the sky. Within the Arctic circle or Antarctic circle, there is continuous daylight around the summer solstice. The opposite event is the winter solstice.
The June solstice is the solstice on Earth that occurs annually between 20 and 22 June according to the Gregorian calendar. In the Northern Hemisphere, the June solstice is the summer solstice, while in the Southern Hemisphere it is the winter solstice. It is also known as the northern solstice.
The 1996–97 South Pacific cyclone season was one of the most active and longest South Pacific tropical cyclone seasons on record, with 12 tropical cyclones occurring within the South Pacific basin between 160°E and 120°W. The season officially ran from November 1, 1996 - April 30, 1997, however, the season ended later than normal with three systems monitored after the official end of the season. The strongest tropical cyclone of the season was Cyclone Gavin which had a minimum pressure of 925 hPa (27.32 inHg). After the season had ended 4 tropical cyclone names were retired from the naming lists, after the cyclones had caused significant impacts to South Pacific islands.
The 1986–87 South Pacific cyclone season was an event in the annual cycle of tropical cyclone formation. A total of 13 tropical cyclones developed during the season.
The 1989–90 Australian region cyclone season was an above average tropical cyclone season. It was also an event in the ongoing cycle of tropical cyclone formation. It ran from 1 November 1989 to 30 April 1990. The regional tropical cyclone operational plan also defines a tropical cyclone year separately from a tropical cyclone season, and the "tropical cyclone year" ran from 1 July 1989 to 30 June 1990.
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of Earth's orbit around the Sun and Earth's axial tilt relative to the ecliptic plane. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical cultures whose number of seasons varies.
During 2005, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 141 systems formed with 94 of these developing further and were named by the responsible warning centre. The strongest tropical cyclone of the year was Hurricane Wilma, which was estimated to have a minimum barometric pressure of 882 hPa (26.05 inHg).
During 2016, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, 140 tropical cyclones formed in bodies of water known as tropical cyclone basins. Of these, 84, including two subtropical cyclones in the South Atlantic Ocean and two tropical-like cyclones in the Mediterranean, were named by various weather agencies when they attained maximum sustained winds of 35 knots. The strongest storm of the year was Winston, peaking with a pressure of 884 hPa (26.10 inHg) and with 10-minute sustained winds of 285 km/h (175 mph) before striking Fiji. The costliest and deadliest tropical cyclone in 2016 was Hurricane Matthew, which impacted Haiti, Cuba, Florida, Georgia and the Carolinas, causing US$15.09 billion in damage. Matthew killed 603 people; 546 in Haiti, 47 in United States, 4 in Cuba and Dominican Republic, and 1 in Colombia and St. Vincent.