倫敦的天氣

Geography and climate
Main articles: Geography of London and Climate of London


London as seen at night by the International Space Station.
Greater London covers an area of 609 square miles (1,579 km²), making it one of the world's largest cities by area. Its primary geographical feature is the Thames, a navigable river which crosses the city from the southwest to the east. The Thames Valley is a floodplain surrounded by gently rolling hills such as Parliament Hill and Primrose Hill. These hills presented no significant obstacle to the growth of London from its origins as a port on the north side of the river, and therefore London is roughly circular.

The Thames was once a much broader, shallower river with extensive marshlands. It has been extensively embanked, and many of its London tributaries now flow underground. The Thames is a tidal river, and London is vulnerable to flooding.[5] The threat has increased over time due to a slow but continuous rise in high water level by the slow 'tilting' of Britain (up in the north and down in the south) caused by post-glacial rebound. In 1974, a decade of work began on the construction of the Thames Barrier across the Thames at Woolwich to deal with this threat, but a more substantial barrier further downstream may be necessary in the near future.

London has a temperate climate with regular but generally light precipitation throughout the year - London is in fact amongst the driest of Europe's capitals.[citation needed] The warmest month is July, with an average temperature range at Greenwich of 13.6 °C to 22.8 °C (56.5 to 73.0 °F). The coolest month is January, averaging 2.4 °C to 7.9 °C (35.6 to 46.2 °F). Average annual precipitation is 583.6 mm(22.98 in), with February on average the driest month.[6] Snow is uncommon, particularly because heat from the urban area can make London 5 °C (9 °F) hotter than the surrounding areas in winter. London is in USDA Hardiness zone 9, and AHS Heat Zone 2.


Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Avg high °C (°F) 7 (45) 8 (46) 10 (50) 14 (57) 19 (66) 21 (70) 23 (73) 22 (72) 20 (68) 16 (61) 11 (52) 9 (48)
Avg low temperature °C (°F) 3 (37) 4 (39) 5 (41) 8 (46) 11 (52) 13 (55) 15 (59) 14 (57) 12 (54) 10 (50) 7 (45) 5 (41)
Source: BBC Weather



http://en.wikipedia.org/wiki/LONDON