January 1, 1977, several villages and settlements were annexed by Częstochowa. As a result, the area of the city expanded from . Pope John Paul II, prayed before the Black Madonna during his historic visit to his Polish homeland in 1979, several months after his election to the Chair of Peter. The Pope made another visit to Our Lady of Częstochowa in 1983 and again in 1987, 1991, 1997 and 1999. On August 15, 1991, John Paul II was named Honorary Citizen of Częstochowa. On May 26, 2006, the city was visited by Pope Benedict XVI. Climate The climate is humid continental (Köppen: Dfb), but still with some oceanic characteristics (Cfb), especially in recent normals. Częstochowa is in one of the hottest summer regions in Poland; although its winters are not the most rigorous, they are colder than the more moderate climates of the west and the Baltic Sea. On average, there are four hours a day with direct solar radiation. In the course of the year, the best insolation is observed in June, due to the greatest length of the day. There are few windless days in Częstochowa. Lull periods on an annual scale account for an average of 9.2%. Western winds prevail here - 18% and south-west - 18.2%. At the same time, they achieve the highest speeds from these directions - 2.2 m/s. The northern winds are least common - 7.7% and north-eastern winds - 7.4%. Economy There are about 26,000 companies registered in Częstochowa. They are represented by the Regional Chamber of Commerce and Industry in Częstochowa. The investment areas form part of the Katowice Special Economic Zone. The main initiator of activities pertaining to the economic development and investments is the Agency of Regional Development. In 2007, in areas surrounding the ISD Częstochowa Steelworks, the Częstochowa Industry Park was established. In 2011, three industry clusters were established – The Cluster of Polymers Manufacturing "Plastosfera", Częstochowa Communal Cluster "Aglomeracja" and the Regional Cluster of Building Industry and Infrastructure "Budosfera". Industry Częstochowa is the main city in the Częstochowa Industrial District, which is the third biggest in the Silesian Voivodship. Since the medieval times, the metal industry has been developing, thanks to the iron ore deposits. The main factories in the city include: The ISD Częstochowa Steelworks – one of the biggest steelworks in Poland, initially established in 1896. The Steelworks produces over 65% of steel sheets