Owing to the rain shadow of the Pindus Mountains, annual precipitation of Athens is lower than most other parts of Greece, especially western Greece. As an example, Ioannina receives around  per year, and Agrinio around  per year. Daily average highs for July have been measured around  in downtown Athens, but some parts of the city may be even hotter for the higher density of buildings, and the lower density of vegetation, such as the center, in particular, western areas due to a combination of industrialization and a number of natural factors, knowledge of which has existed since the mid-19th century. Due to the large area covered by Athens Metropolitan Area, there are notable climatic differences between parts of the urban conglomeration. The northern suburbs tend to be wetter and cooler in winter, whereas the southern suburbs are some of the driest locations in Greece and record very high minimum temperatures in summer. Snowfall is infrequent. The last time snow fell in Greater Athens area and Athens itself, was 14-17 February 2021; snow blanketed the city from the north to the very south suburbs with depth ranges from 7-8 cm up to 40 cm. (The main range for 