“Improbable as it is for snow to fall during August, history tells of a snowfall that seemed more impossible, namely in Rome, Italy. August 5, 352, snow fell during the night in Rome.
There lived in the Eternal City a nobleman, John and his childless wife, who had been blessed with much of this world’s goods. They chose the Mother of God as the heir to their fortune, and at the suggestion of Pope Liberius, prayed that she might make known to them how to do this by a particular sign.
In answer, the Virgin Mother during the night of August 5, appeared to John and his wife and also to the Holy Father, Pope Liberius, directing them to build a church in her honor on the crown of the Esquiline Hill. And what would be the sign that John and his wife had requested?
“Snow will cover the crest of the hill.”
Snow rarely falls in Rome, but the flakes fell silently during that night, blanketing the peak of the historic hill. In the morning the news quickly spread and crowds gathered to throng up the hill and behold the white splendor. The snow had fallen in a particular pattern, showing the outline of the future church. When it became known that the snow was a sign from Mary, the people spontaneously added another to her long list of titles, Our Lady of the Snows.”
Acknowledgement: https://www.roman-catholic-saints.com/our-lady-of-the-snows.html