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.
Winter (November - mid April) Weather: Winters can be bitterly cold in West Yellowstone, but at times warm Chinook winds come blowing in and push temperatures up into the 40s. Winter temperatures during daylight hours often hover near zero but can get into the upper 20s. Nighttime temperatures commonly go subzero.