Pluriannual series of phenological observations represent a valid synthetic indicator of climatic trends, especially at local scale. In Switzerland, the systematic net of phonologic monitoring was created in 1951 and then progressively extended. In this study data of 11 stations of southern Switzerland for the period 1971-1995 are presented. The results confirm the strong annual variability of the phenological data, and of the spring phonologic phases in particular. The classification of the years in phenologically early and phenologically late allows to distinguish in the decade 1975-1986a phenologically late period and an early period between 1989 and 1995. These results are in good coincidence with the climatologic state of the art. Among the phenophases that showed a significant evolutionary trend in the study period an overbalance of autumn phenophases with the trend towards a postposition of the end of the vegetation period was registered.