Warsaw experiences an oceanic climate, denoted by ''Cfb'' by the Köppen climate classification. However, the city has clear humid continental influences (Köppen: ''Dfb''), and the city is defined as such with old data, prior to the recent effect of climate change and the city's urban heat island. Meanwhile, by the genetic climate classification of Wincenty Okołowicz, it has a temperate "fusion" climate, with both maritime and continental features.