Six to nine months puts you right in the beginning of the hot season for the southwest (Las Vegas and southern Utah) to the end of summer. It was 105F on June 6, the day I arrived in Las Vegas to live here. I remember it well. Thought I had landed in Hell compared to the beautiful Spring day I had interviewed for a job here. You can ride early in the morning but probably want to avoid mid-day and it will limit the number of hours you can ride. Carrying enough water to survive those temperatures is another problem.