The average high temperature in Las Vegas is a bit over 80 in October (that's about 27 C for our international guests). It can typically be up to 10 degrees higher or lower, as temps in the desert vary widely depending on conditions.

I'm a desert boy, so perhaps that colors my perceptions somewhat, but I don't think 80 or even 85 qualifies as "hot." Most of us would consider it beautiful weather! Warm, balmy, etc. :) Not much in the way of rain, either. About 87% of October days are either clear or only "partly cloudy." The city must have been unseasonably "warm" while you were there? Bob