summer solstice is the first day of summer, and why it's the longest day of the year—but not the hottest.
Earth's oceans and atmosphere act like heat sinks, absorbing and re
radiating the sun's rays over time. So even though the planet is absorbing lots of sunlight on the summer solstice, it takes several weeks to release it. As a result, the hottest days of summer usually occur in July or August.