TIROS pictures of mountain lee waves produced by airflow over four different mountains are discussed. The wavelengths of the observed cloud patterns are compared to the mean wind in the troposphere as suggested by Corby (1957). In three of the four cases examined, Corby', relationship worked well. In the fourth case, it was found that smaller thermal stability was associated with an average wind speed lower than Corby's relation suggests. This is in agreement with theory. Other criteria, such as proper wind direction, needed to produce mountain waves are also found in these cases. Thus pictures of mountain waves may often be useful in estimating certain atmospheric parameters in those mountainous areas where conventional data may be unavailable. Abstract TIROS pictures of mountain lee waves produced by airflow over four different mountains are discussed. The wavelengths of the observed cloud patterns are compared to the mean wind in the troposphere as suggested by Corby (1957). In three of the four cases examined, Corby', relationship worked well. In the fourth case, it was found that smaller thermal stability was associated with an average wind speed lower than Corby's relation suggests. This is in agreement with theory. Other criteria, such as proper wind direction, needed to produce mountain waves are also found in these cases. Thus pictures of mountain waves may often be useful in estimating certain atmospheric parameters in those mountainous areas where conventional data may be unavailable.