According to Allcitycodes, Netherlands is a small country located in the Benelux region of Western Europe. It has an area of 41,543 km2 and a population of 17 million people. The terrain consists mostly of flat coastal plains in the west and south, with hills and mountains in the east and north. The climate is temperate maritime with mild winters and cool summers. Rainfall averages around 800 mm annually, with most rain occurring during the winter months. The area code for Netherlands is +31. This code is used when dialing from outside Netherlands to any other phone number within it. Additionally, to call a cell phone or landline inside Netherlands from another country you must dial 00 + 31 + area code (without 0) + telephone number. There are currently 28 area codes for different regions across Netherlands; Amsterdam (20), Rotterdam (10), Utrecht (30), Eindhoven (40), Tilburg (13), Groningen (50) and The Hague (70). For example, to call a phone number in Amsterdam, you would dial 00 + 31 + 20+ telephone number. Netherlands also has mobile networks which are operated by KPN, VodafoneZiggo and T-Mobile which all use GSM networks with 3G/4G coverage available on all networks. To call a mobile device within Netherlands you must dial 00+31+ mobile network prefix + telephone number where the mobile network prefixes are either 6 or 7 depending on whether you are calling a KPN or VodafoneZiggo device respectively. Check physicscat for Netherlands in 2013.