Summer begins at 9:54 am MDT.
In the Northern Hemisphere, the June solstice (aka summer solstice) occurs when the Sun reaches both its highest and northernmost points in the sky. It marks the start of summer in the northern half of the globe. (In contrast, the June solstice in the Southern Hemisphere is when the Sun is at its lowest point in the sky, marking the start of winter.)
The word “solstice” comes from Latin solstitium—from sol (Sun) and stitium (still or stopped), reflecting the fact that on the solstice, the Sun appears to stop moving in the sky as it reaches its northern- or southernmost point. (Courtesy of the Old Farmer’s Almanac.)