In this study spatial and temporal variations of climatic growing season parameters in western Anatolia, Turkey, during 1966-2015 are analysed. The beginning of the growing season (end of the growing season) for all threshold values of 5, 7 and 10 C is delayed (advances) from the southwest to the northeast over the study area. The growing season length (GSL) increases from northeast to southwest. The growing season start (GSS), growing season end (GSE) and GSL are strongly correlated with elevation, low-elevation stations having earlier GSS, later GSE and longer GSL than stations at higher elevations. The regional average GSS shifted 7.3, 10.0 and 10.5 days earlier, while the regional average GSE moved 4.8, 6.1 and 6.2 days later, increasing the GSL by 12.0, 16.6 and 15.9 days for 5, 7 and 10 C, respectively. A comparison of mean values between subperiods documented significant changes at more than 50% of sta-