This paper represents an analysis of the time series of selected meteorological parameters: mean, maximum and minimum air temperatures, sums of effective air temperature values with the temperature thresholds 5ºC and 10ºC, average precipitation quantities, number of days with frost, potential evapotranspiration and water balance. Study included data from 10 meteorological stations located on the territory of the Republic of Slovenia for the period 1961-2011. Analyzes were performed on a seasonal and annual basis. The obtained results showed a statistically significant positive trends of temperature parameters and potential evapotranspiration, while average precipitation quantities and water balance had a negative trend on the seasonal and annual basis. Positive trend of number of days with frost is present on most stations. In the second part of this paper, the obtained results were associated with the phenological data (data about the development of plants) in order to determine the intensity of correlation between them.