Windows reduce the sidelobe leakages from the spectrum when applied to finite length time domain sequence. Adjustable windows can be used to control the amplitude of sidelobes with respect to main lobe. This paper presents the effect of window parameter in Dolph-chebyshev, Kaiser, Gaussian and Tukey windows on the Signal to Noise Ratio(SNR) of radar returns and proposes an optimum value of window parameters with which data may be weighed. A comparative study is made on the improvement of SNR using these variable windows.