Is there a correlation between a cold winter and a hot summer in Italy? Let's say that there is a weak correlation, if we look at the last decades: the winters 2002/03 and 2011/12, for example, had very cold periods in Italy and the following summers were exceptionally hot, especially in 2003, while the very mild winters 2013/14 and 2015/16 were followed by moderate and not excessively hot summers. But the winter 2001/02 was even colder but the summer 2002 was moderate and unstable in July and August, although very hot in June and a partially similar discourse applies to the cold winter 2004/05, followed by a summer not very different from that of 2002. Again, the very hot summer 2003 was followed from the winter of 2003/04 with six intense cold waves, but the summer of 2019, also very long and hot, was followed by a very mild winter, the 2019/20.
Therefore the correlation is very weak and has no scientific basis, indeed with global and local warming in progress it has further weakened.