Absolutely not, those temperature are too low for Edinburgh, in winter the Atlantic ocean effects don't make it possible to reach -20°C in the city. It is said also in the link you have posted :"Gli inverni sono lunghi ma non sono freddissimi considerando che le temperature scendono di rado sotto i 0 °C"
Of Course, it is colder if we condider annual average temperatures, but we are talking about winter in this thread!
But in winter Milano for example is colder than Edinburgh, look at this data set:
Milano Linate
Edinburgh Royal Obs.
Milano avarage temperatures in December, January, February are lower than temperatures in the same months in Edinburgh. Milano is 1.8°C colder than Edinburgh in the coldest month of winter (january), it is much
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