Solar ultraviolet flux changes associated with the 27‐day solar rotational period cause corresponding variations in mesospheric ozone near the maximum of the 11‐year sunspot cycle. This statement is based on a correlation and spectral analysis of ozone mixing ratios, deduced from Solar Mesospheric Explorer satellite‐based measurements of 1.27‐µm O2airglow emission and solar flux observations made from the same spacecraft in 1982. With the Lyman α flux taken as an indicator of solar ultraviolet variability, spectral analysis shows a primary period of 27.1 days with a secondary period of 13.5 days. The 27.1‐ day period is observed in the ozone mixing ratio data together with other periods, including 13.5 days. Both a classical statistical analysis and a time series treatment show that for 244 days there is a correlation between ozone and solar flux near 50 km and between 65 and 70 km. Calculations predict a positive correlation over the entire mesosphere if there is no change in temperature accompanying the solar flux. Lack of correlation is temperat