In July temperatures in Jackson Hole, Wyoming tend to see daytime highs of 70s to 60s and nighttime lows in the 50s to high 30s. Planning to dress in layers is ideal with warm weather clothing for the day and some form of jacket or similar for night time. It's also a good idea to bring a rain coat in case of rain which can occur sporadically, although your weather is typically clear blue skies and sunshine during this time of the year.
Jackson Hole is 6,237 feet above sea level.
A rental car is a must for general transportation in the area. Numerous car rental companies are available on site at Jackson Hole airport. Jackson Hole does have Uber and Taxis. However, you should definitely rent a car for your general transportation needs while there.