For the outdoorsy types, rain can be especially damping on the spirits, so use your indoor time to your advantage by taking your dog with you to Bass Pro Shops in Las Vegas. They're dog-friendly and have a massive selection of products for both you and your pooch to choose from for your next outdoor adventure.
Since most art galleries don't serve food, it's easy enough to make them accessible for dogs. Very few will out of principle alone, but places like Jana's Red Room in the Art Factory is dog-friendly and will allow them to come in and check out the newest pieces with you.
Surprisingly enough, even some of the most regal hotels in Las Vegas have dog-friendly accommodations. Some will even go so far as to offer custom beds, bowls, toys, and clean-up services, so if you're planning a vacation, even if it's just for a day or two, make sure to see which ones offer the best doggy amenities.