When does winter start?

The dates when the seasons begin and end are different in every country. In Ireland we say winter starts after Halloween as November, December and January are the three darkest months of the year. This makes a lot of sense as we dont get very cold, icy winters like some other countries. In colder countries Dec 1st or even the winter solstice(Dec 21st this year) is regarded as the start of winter. Read more here.