Lake Tana is the largest Lake in Ethiopia which has been invaded by water hyacinth since 2011.rnHowever, there is lack of reliable estimates of annual and seasonal water hyacinth distributionrnand extent. Therefore, this study aims to assess the spatio-temporal pattern of water hyacinthrnand itâ€™s dynamics with seasonal climate variability and impact on evapotranspiration usingrnLandsat 7 ETM+, Landsat 8 OLI, Sentinel 2 and meteorological data. The area of waterrnhyacinth and surface area of the Lake were mapped using supervised, unsupervised and manualrndigitizing image classification techniques. The trend of water hyacinth was determined usingrnMann-Kendall trend test and the impact of climate variability on water hyacinth spatialrndistribution was studied using Pearson correlation coefficient. The evapotranspiration and waterrnlosses were estimated from reference evapotranspiration computed using FAO-56 PenmanMonteithrnmethodrnandrnarncroprncoefficientrnvaluernofrn0.65rnandrn1.90.rnThernresultsrnofrnthernstudyrnrevealedrnrnthatrnrnthere was a statistically significant increasing trend in annual spatial coverage of waterrnhyacinth. The annual coverage areas of water hyacinth increased by 96% from 134ha in 2011 torn3019ha in 2019. However, the surface area of the Lake showed a decreasing trend. A total ofrn1834ha of the surface area of the Lake (0.6 % of the average surface area of the Lake) has lost rnover the last nine years. The annual maximum lake surface area was 306,399ha occurred inrn2015 and the minimum was 302,952ha in 2019. The monthly and seasonal spatial-temporalrndynamics of water hyacinth in Lake Tana exhibit a periodic cyclical pattern, reaching thernhighest peak in Bega followed by a decline to the least coverage level in Kiremt season. Thernhighest growth areal extends of water hyacinth was 3830ha in 2018 November while, thernminimum area was 396ha in 2017 July. The monthly surface area of the Lake was varied fromrn298,392ha in 2016 June to 317,257ha in 2018 July. The seasonal average surface area of thernLake was ranged between 301,817ha in Belg and 307,471ha in Kiremt season. The average dailyrnevapotranspiration of water hyacinth in Lake Tana from 2016 September to 2018 December wasrn2.39 and 6.99 mm/day, and the average water loss in the Lake due the weed evapotranspirationrnwas 35, 678 and 104,290 m3/day using Kc of 0.65 and 1.90 respectively. The total amountrnvolume of water loss in Lake Tana from 2016 Sep to 2018 Dec was between 30,397,918 mrn andrn88,855,452 m,rn3rn3rn the average value represents 0.21 % of the volume of the Lake using a Kc valuernof 0.65 and 1.90. The Pearson correlation of monthly water hyacinth and rainfall was significantrnmoderately negative (r= -0.63, p=0.03). The correlation of mean monthly temperature and windrnspeed with water hyacinth was negative (r = -0.34, p = 0.28) and (r = -0.59, p = 0.04)rnrespectively. The seasonal correlation of the area of water hyacinth with rainfall and wind speedrnwas insignificant moderately negative (r= -0.72, p=0.49) and (r= -0.62, p=0.57). Lowrninsignificant negative correlation (r = -0.36, p = 0.76) with mean temperature was also attainedrnin seasonal period. In general, the climate variability in Lake Tana Basin showed a less andrninsignificant contribution for distribution and spread of water hyacinth in study period.