On the day of the summer solstice, the sun appears at its highest elevation. Summer solstice is the time of year when the sun has peak sunshine in the Northern Hemisphere. Summer solstice breakdownWhat we know:Friday, June 20, is the longest first day of the year north of the equator, where the solstice marks the start of astronomical summer. During the Northern Hemisphere’s summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. What they're saying:According to the National Weather Service, the longest day of the year is typically not the warmest day of said year.