While it rarely rains much in LAS, wind issues can cause certain events to close. Two days is too short for a first time visit; since you note New York (City?) as your location, you can go to Atlantic City (or even Resorts World in Jamaica) for gambling--so confine your activities in LAS to things you couldn't do elsewhere.
A $8.00 Deuce day pass lets you ride on the Deuce (or SDX) strip busses, so you can get a quick view of the city.