Clouds play an essential role in the global energy budget but the impact of anthropogenic aerosols on clouds is still poorly understood. We use fifteen-minute temporal resolution geostationary satellite data to study the temporal evolution of polluted cloud tracks detected in the European part of Russia. Previous analysis of polluted cloud tracks shows that cloud water response to aerosols is bidirectional. Here, we show that the day-night contrast in cloud responses partly explains the bidirectional cloud water responses. We have data only for sunlight hours, but we can interpret the cloud responses detected already since the early morning as night-time responses. On average, the decrease in cloud water offsets 46% of the Twomey effect in the study area while the decrease happens during night-time, probably due to aerosol-enhanced entrainment. In the afternoon, cloud water is more likely to increase in the polluted clouds, most probably due to suppressed precipitation. Our findings highlight the need to better account for the temporal evolution of cloud responses to estimate the aerosol radiative forcing more accurately.