Human's unwise and ineffective exploitation behavior has caused losses of the vital natural resources, soil and water, which will definitely leave the future of the next generation in jeopardy. As a result of human intervention and natural causes most lakes in Ethiopia are shrinking in size while others are showing increase in volume. The intensive exploitation, beyond its regeneration rate, of the Lake Haramaya for water supply and agricultural purposes by the community within and outside its catchment boundary has led to its extinction. Although, some studies have been conducted on land use/land cover dynamics, the focus given to quantification of temporal variability lake surface area and the impact of weather variability on the lake water was inadequate. Hence, this study was conducted with the prime objective of mapping/quantifying the temporal lake surface area fluctuation using time series remote sensing images and investigating the impact of weather/climate variability on the lake. After acquiring Landsat images of the years 1985, 1995, 2003, 2010 and 2016 over the dry Haramaya Lake basin (path/row 166/54), the Modified Normalized Difference Water Index (MNDWI) and the Normalized Difference Vegetation Index (NDVI) were used for enhancing and extracting the open water surface of the lake. All of the enhanced images display a trend of decreasing lake surface water area with an average shrinkage of 23.6% between the year 1985 and up to its disappearance. After 2000 the lake surface area shrinkage was at its maximum which has a direct relation with the occurrence of dry weather as a result of relatively higher temperature and low rainfall between the years 2000 to 2003.