Sea level. Mean sea level (MSL) (abbreviated simply sea level) is an average level of the surface of one or more of Earth's oceans from which heights such as elevations may be measured.
Dates: September - October. Weather: Autumn in Wyoming is a delight. Many locations will see snow in mid-September, but it doesnât get to be real winter until late November. During October and November youâll discover a warm Indian Summer, with cool nights and beautiful changing colors. Early freezes in the fall are common.
Weather in Yellowstone during September to November. The best time to visit Yellowstone is between September and November or March and May. From September to November, the weather is beautiful, with mild, sunny days, cool crisp mornings and evenings and pleasant nights. It can become quite cold though, so always take extra thermals, long tops and a good jacket to be safe.