There's a misconception that the warmest time of the day is noon. It may feel hotter at the noon hour because we're getting the most energy from the sun at that time. However, the earth is storing incoming energy or heat throughout the day. The longer the sun is out, the warmer the air becomes. Temperatures will continue to climb as long as the earth is receiving more incoming heat than it's radiating back into space. The re-radiation happens later in the day, making the hottest part of the day between 4 p.m. and 6 p.m. during the summer. Temperatures will warm very quickly during the morning hours because of the mixing of two air masses. Overnight, cooler air sinks to the valley from the mountains. As the sun rises, the solar radiation heats the ground. The difference in temperature between the two air masses creates turbulence, which results in the quick warm-up. For example, the temperature can be 65º at 7 a.m., but jump 20º just three hours later. So, if you're planning your summer days to spend the most time outdoors as you can while strategically avoiding the absolute peak of the day's heat, you might want to plan for a later lunch, and then have at it once again in the later afternoon when the heat of the day starts to exit.
