Although we've already had the summer solstice -- the day of the year with the most sunlight, usually around June 20 or 21 --temperatures can continue to warm in many areas since "the rate of heat input from the sun during the day continues to be greater than the cooling at night for several weeks, until temperatures start to descend in late July and early August."

Of course, this is based on typical temperatures based on historic data, so this or any year's actual summer temperatures depend on current weather and climate patterns.