Excess nutrient loads, particularly nitrogen (N) and phosphorus (P), play a significant role in the degradation of global water quality and aquatic ecosystems. The amount of these nutrients in rivers is significantly affected by the increasing hydroclimatic variability, coupled with changes in land use intensity. This study assessed trends over 30 years in total nitrogen (TN) and total phosphorus (TP) in the Aurajoki catchment, Southwest Finland, and evaluated how land use intensity and seasonal hydroclimatic variability influence nutrient dynamics. The utilized data consisted of long-term monitoring records of nutrient concentrations, discharge, temperature, precipitation, and the Landsat imagery series. Prior to the analyses, the Standardized Precipitation Index (SPI), Accumulated Winter Season Severity Index (AWSSI), and Normalized Difference Vegetation Index (NDVI) were used to characterize hydroclimatic variability and land use intensity. Data were analyzed using Mann-Kendall statistics to assess trends and generalized additive mixed models (GAMMs) to evaluate the impact of land use intensity and hydroclimatic variability. Results showed a decrease in annual TN concentrations and TN loads, while TP trends remained stable. The seasonal trend test revealed significant TN and TP increases in fall and decreases in spring. The modelling results revealed that NDVI had a significant impact only on nutrient concentrations, whereas the effects of hydroclimatic class were limited to nutrient loads and varied according to different combinations of season and NDVI. These findings highlight the relevance of seasonal hydroclimatic variability and land use intensity when assessing nutrient dynamics, particularly in the context of climate change and water protection strategies.