Table 9. — Columbia River at Rock Island 

 Average monthly water temperatures °F., 1933-1955. 

 Data from Puget Sound Power and Light Company, and 

 U. S. Fish and Wildlife Service 



Avg. 39.3 37.2 39.3 UU.5 50.0 55.2 61.5 6Uo8 63.5 58.5 50.6 UU.l 



* Averaged to nearest half degree for most of 1933-19U9 as ten^jeratureo were 

 recorded to nearest degree. 



U8 



