Climatology is the study of "average weather". Meteorology is the study of day-by-day variations in the weather. Climatology, in contrast, is the study long-term weather patterns and variations, usually over a number of years. It is concerned with both the description of climate and the analysis of the causes of climatic differences, and more recently climate changes and their practical consequences. Climatology investigates the same atmospheric processes as meteorology, but also seeks to identify the longer-term influences on climate, such as the circulation of the oceans and the small variations in the intensity of sunlight.