The position of Crete in the middle of the Mediterranean, her geographical placement with her main axis directed from the west to the east and the existence of high mountain ranges are some of the factors that greatly influence the annual precipitation the island receives. The weather systems that influence the climate of Greece move from northwest to southeast, carrying humidity from the Ionian Sea. The southern weather systems influence more the climate of Crete, and as result receives most its annual rainfall during the winter and mainly in its western part and high in the mountains. In this way, there is an uneven rainfall distribution in the island, and in combination with the higher temperatures that prevail in the southeast part of the island, a wide range of climates and microclimates are created according to region. Therefore, the Prefecture of Chania features more water streams, lakes and rivers, and north Crete has lower temperatures in comparison to south Crete. For these reasons, the southern shores of Heraklion and Lasithi are faced with more drought problems.