Based on the meteorological data from 2008 to 2009,which were collected from an automatic observation system over water surface in Erhai and an automatic weather station in Dali National Climate Observatory,the diurnal and seasonal variations of wind speed,wind direction,air temperature,relative humidity,air pressure and precipitation were analyzed and compared.Results show that there is a local circulation in surface layer over the Erhai lake basin,which is caused by the lakeland breeze,the mountainvalley wind and the gorge wind affected by the local complex terrain and the Erhai lake.The prevailing winds are southeast in the day,and southeast and west southwest at night over the water surface.The prevailing winds are east southeast in the day,and static wind and west northwest at night over the land surface.The annual mean wind speed is 29 m／s over the water surface and 24 m／s over the land surface.The annual mean air temperature is 168 ℃ over the water surface and 160 ℃ over the land surface.Air temperature,relative humidity and air pressure show significant diurnal variations over the water and land surfaces.The occurrence time of maximum and minimum of air temperature and relative humidity over the water surface is later than that over the land surface.The annual rainfall mainly takes place from May to October.