Re: Water temp?
At Lake Mead, in October you can still get water temps in the low 80's. The temps drop sharply in Nov-Dec to the mid to low 60's. Water temps average in the 50's Jan through April, then climb back into the mid 60's in May, Mid 70's in June.
The Colorado River Temperatures vary greatly depending on what section of the river you're boating on. Below the dams are much colder, obviously, than farther down river. You can see river temps in the 40's below Hoover Dam, and in the 50's & 60's elsewhere.
Welcome and have fun!