The cyclic phenomenon in the monthly mean temperatures in Matsue over 35-yaer period(1941-1975) and that in Hamamatsu over 93-year period(1883-1975) were well described by two-term Fourier equations, Y = 14.2712-10.6048a_1-2.6665b_1＋0.1938a_2＋ 0.6326b_2 and Y = 15.2399-9.8615a_1-2.6368b_1-0.3459a_2+0.5956b_2, respectively. A correction for differences in the length of the successive months with Craddock's weighted multipliers proved of minor importance relative to other errors in fitting a two-term Fourier curve. In Matsue, the average maximum temperature occurred on August 2.88±3.17 and the minimum on January 23.88±4.37. Those in Hamamatsu occurred on August 7.30±2.73 and January 23.07±2.72. The maximum temperature averaged 25.7951℃ and the minimum 3.7000℃ in Matsue. Those in Hamamatsu averaged 25.5363℃ and 4.9387℃, respectively Observed monthly variances of the mean monthlytemperatures in Matsue were greater in winter season centering around February and also in summer season centering around August than other seasons. However, that in Hamamatsu were only in winter season than others.