02 February 1956,
In Euskal Herria, an impressive temporary cold began, almost entirely snowy that night. It lasted about a month, although the temporal and cold did a little break. For example, in San Sebastian, due to the cold from Europe, there were 19 days of ice in total and many days the thermometer was not raised by 0 °C. The cold caused many deaths in Europe, especially people living on the street.
Source:
Wikipedia – Snow and Cold in February 1956