Long-term variation of phenology over the last 50 years in Kagawa Prefecture has been investigated. The first date of flowering of Someiyoshino (Prunus yedoensis Matsum) has shown a significant advance of 6 days over 50 years, and the average first date of flowering has shifted from 31 March in the 1950s to 27 March in the 1990s. The first date of yellow coloring of the leaves of Ginkgo biloba L. has shown a delay of 12 days over 50 years, and the average first date has shifted from 20 November in the 1950s to 30 November in the 1990s. These trends in phenology have been especially significant since the 1980s. These results coincide with a trend toward local warming and indicate that spring tends to come earlier and winter tends to come later than in the past.