The climate of the Maltese Islands

Abstract

Existing meteorological data were analysed such as to present a picture of what the normal values of the main climatic features of the Maltese Islands are, how they vary and if there are any long term trends in this variation. These climatic parameters and their fluctuations are related to the ecology of the Islands in order to determine whether there is any relationship between climate and the main vegetational communities. The study makes use of climatic data obtained from the Annual Abstract of Statistics which gives records of rainfall measured in Valletta for the period 1854-1950 and from the Luqa Meteorological Office for the period 1851-1986. Records of data of the rainfall amounts at different rain-gauges distributed around the Maltese Islands were obtained from the Water Works Department. The climate of the Maltese Islands is classified as Mediterranean, with characteristic biseasonality; six months of drought alternate with six months of mild rainfall. This rainfall is highly variable; some years are excessively wet while others are extremely dry. However, the rainfall does not appear to follow any periodic cycle or trend and has remained fairly constant during the last century. Temperatures are moderate and never fall too low for adequate plant growth although the grass temperature may fall below zero in all the months October to May. The predominant wind of the Maltese Islands is the north-westerly and the Island receives a great deal of sunshine all the year round. Evapotranspiration in the Maltese Islands is high and this results in the loss of water such that only 16% of the rainfall infiltrates into the substratum and can be used by the vegetation. The amount of water available influences the type and distribution of the vegetation with garigue being dominant in regions of low water availability and maquis being dominant in regions where more water is available. Thus, climate acts as a controlling factor in the determination of the relief, the formation of soil and in the distribution of vegetation.