Weather is an important variable to form the characteristic natural ecosystem of the region along with topography and soil. Since the ecosystem change is expected by the global warming, the preparation for the change has to be made to accumulate the investigative data for the relationship on local weather and ecosystem. As the study method, the measurement data and sea surface temperature data were analyzed and the atmospheric model was performed. As the result, the weather characteristics, changing patterns and the causes of the weather change in Ulreungdo and Dokdo regions could be analyzed. For the last 67 years since the weather measurement was started in Ulreungdo, annual temperature elevation rate was 0.013oC and 0.88oC was elevated for 68 years, and the temperature elevation rate during the winter season recorded the highest elevation rate of 0.024oC/year. The amount of rainfall in Ulreungdo has been significantly increased recently. The strength of a typhoon that had affects on the peninsula and the increase of rainfall was mainly attributable to the increase of sea surface temperature alleviation at the East Sea. Sea surface temperature near Ulreungdo and the weather of the Ulreungdo weather station has high correlation each other. The acute sea surface temperature elevation could be assumed to cause the temperature elevation in Ulreungdo. According to the weather model of MM5, the simulated effect of sea surface temperature elevation on the atmospheric temperature resulted the average 1.3oC temperature increase in Ulreungdo as the sea surface temperature was increased 2oC. Therefore, it was able to confirm that the major reason of temperature elevation at the Ulreungdo weather station was attributable to sea surface temperature elevation.