Observations from 1890 to 2020 of ice phenology for 101 Norwegian lakes were used to detect variation in ice phenology. The average date of ice break-up occurred later in spring with increasing elevation, latitude and longitude. The average date of freeze-up and the length of the ice-free period decreased with elevation and longitude. Lakes were completely frozen later recently in autumn. There is a significant trend for earlier break-up, later freeze-up and completely frozen lakes after 1991.