And since the sun will appear to describe such a high arc across the sky, the duration of daylight is now at its most extreme. In fact, north of the Arctic Circle, which encompasses northern Alaska, far-northern Canada, much of Greenland as well as the northernmost parts of Norway, Sweden and Finland, the sun now remains above the horizon for an entire 24-hour day, leading to the effect known as the "midnight sun."
However, contrary to popular belief, the earliest sunrise and latest sunset do not coincide with the summer solstice. For mid-northern latitudes, the earliest sunrise actually occurred on June 14, while the latest sunset is not due until June 27. [Where to Be for Summer's Solstice Kickoff]
If the insolation — the total energy received from the sun — alone governed the temperature, we should be experiencing the year’s hottest weather right now.
But the atmosphere in temperate regions continues to receive more heat than it gives up to space, a situation that lasts a month or more, depending on the latitude. Though it depends on the local climate, most locations see the hottest part of the year occurring in late July. A reverse process occurs after the winter solstice in December; most places see their coldest weather in late January.