This paper proposes applying the statistic analysis method for determination of static conductor thermal rating. The spectrum of the maximum current of conductor over a year is first calculated using Typical Meteorological Year (TMY2) data set as weather data and IEEE Standard 738-1993 as computation engine. The statistic analysis is then performed to calculate the cumulative distribution function (CDF) of the maximum current. Finally, the static conductor thermal rating can be determined based on the risk level which utilities are willing to take. The statistic analysis method helps system planners to determine the static conductor thermal rating by quantifying the risk of a conductor’s actual allowable maximum current higher than the static rating. This proposed method is applied to determine the static conductor thermal rating of different zones within Rocky Mountain and Desert Southwest area.