If you had dropped a little deeper [depends on air/surface temp] you would SEE [pycnocline] the thermocline in Tahoe [always found below 90ft]....once below it is 40F..."brass monkey cold"...first wet suits we in the Nevada Desert Divers [50s] used, already mentioned from Dive & Surf Dive Store Redondo Beach, were 3/16", high waist, beaver tail, separate hood and we often got dressed inside a vehicle during blizzards...so to echo what others have said, like Eric, within limits you adjust to the environment before and during dives....all good! Never optimal but close enough....and like Eric, getting wet and feeling the water is for me an essential part of being a diver....with the half dozen different dry suits I have owned, I always come back to a wet suit...
May not be every one's cup of tea, but for me the feel and mobility of a wet suit can't be beat...oh, and I am an addicted freediver.