In this study, the application of an efficient method, the CSP method, to the temperature and precipitation data is investigated on different regions over Iran in two statistical periods, in order to evaluate the climate variability. For the surface temperature and precipitation, the main quasi-periodic spectral components in different regions of the country were shown without being affected by noise. The annual component of the precipitation includes 50 to 60% of the variance in most parts of the country. However, the impact of this component is less than 20% in the southeast and northwest of the country. A strong semi-annual component was found only in the northwestern region. For surface temperature, the annual component includes more than 90% of the variance in all regions of the country. Significant changes in the spectral content of the precipitation data were observed in two separate statistical periods, but these changes were negligible for temperature.