This paper describes our newly developed high-resolution temperature observational system called Extended-METROS, which has been deployed in the Tokyo Metropolitan Area since 2006. Some climatological mean temperature charts using Extended-METROS data are analyzed in terms of urban climatology, and detailed urban heat island temperature patterns are clarified. Rainfall measurements were set up from August 2010 at 40 points in the Tokyo Metropolitan Area. The relationship between urban heat islands and local-scale heavy rainfall patterns in urban areas will also be analyzed based on our high-resolution meteorological observation system.