Pros and limits
Strengths
Simple equipment. Works well in dry heat. Brings in fresh air.
Limits
Weaker during monsoon humidity. Needs water, an air exit and upkeep for hard water.
The NWS defines monsoon season as June 15 to September 30 (see the NWS Climate of Las Vegas summary). If you need cooling that's reliable on humid days, compare it with a mini-split.
FAQ
Do swamp coolers work in Las Vegas?
They work best when humidity is low, which describes much of the Las Vegas year. They lose effectiveness during humid monsoon spells.
Do I need to open a door or window?
Yes. Evaporative coolers need an exit for the air. Without one, humidity builds up and the cooling stops.
What maintenance do they need?
Water supply, pads, and regular cleaning to manage mineral buildup from hard water. Ask about upkeep.