Summer officially begins astronomically in Utah on Friday, June 21st, at 9:54 MDT. The northern hemisphere on the solstice is the longest day of the year. Dawn comes early and sunsets come late, with short nights and less time to enjoy the night sky.
The term solstice means “sun stopping.” This refers to the point on the horizon where the sun appears to rise and set, then stops and reverses direction. On this day, the sun rises north of east, and sets, north of west. The sun at that moment is directly over the Tropic of Cancer. The sun will travel no further north as seen from the Earth and is at its highest point in the sky.
After June 21st, the sun reverses direction and moves lower in the sky until it reaches winter solstice in December. A common misunderstanding is that the Earth is closest to the sun on the summer solstice, but in fact, the Earth is the farthest from the sun on June 21st.
The Earth's distance from the sun has little effect on the seasons, instead, it’s the tilt of the Earth’s rotational axis at 23 1/2 degrees that cause the seasons. The hottest day of the year doesn’t come for another month or so due to the amount of time it takes for the land and ocean to warm up.