new seats for the City of York, in time for the general election in 2010. These are York Central, which covers the inner urban area, and is entirely surrounded by the York Outer constituency. Ceremonial York is within the ceremonial county of North Yorkshire and, until 1974, was within the jurisdiction of the Lord Lieutenant of the County of York, West Riding and the County of The City of York. The city does retain the right to appoint its own Sheriff. The holder of the Royal dukedom of York has no responsibilities either ceremonially or administratively as regards to the city. Geography Location York lies in the Vale of York, a flat area of fertile arable land bordered by the Pennines, the North York Moors and the Yorkshire Wolds. The city was built at the confluence of the Rivers Ouse and Foss on a terminal moraine left by the last ice age. During Roman times, the land surrounding the Ouse and Foss was marshy, making the site easy to defend. The city is prone to flooding from the River Ouse, and has an extensive network of flood defences with walls along the river, and a liftable barrier across the Foss where it joins the Ouse at the "Blue Bridge". In October and November 2000, York experienced the worst flooding in 375 years; more than 300 homes were flooded. In December 2015 the flooding was more extensive and caused major disruption. The extreme impact led to a personal visit by Prime Minister David Cameron. Much land in and around the city is on flood plains too flood-prone for development other than agriculture. The ings are flood meadows along the Ouse, while the strays are open common grassland in various locations around the city. Climate York has a temperate climate (Cfb) with four distinct seasons. As with the rest of the Vale of York, the city's climate is drier and warmer than the rest of the Yorkshire and the Humber region. Owing to its lowland location, York is prone to frosts, fog, and cold winds during winter, spring, and very early summer. Snow can fall in winter from December onwards to as late as April but quickly melts. As with much of the British Isles, the weather is changeable. York experiences most sunshine from May to July, an average of six hours per day. With its inland location, summers are often warmer