Why Isnt the Summer Solstice the Hottest Day of the Year

For most of China, the dog days of summer are just around the corner. July and August bring a special kind of misery where a quick lunch run can feel like you’re losing a layer of skin. Late last August, a colleague and I pondered why summer drags on for so long. His theory involved some myth I can’t recall, but I confidently declared, “It’s the concrete. It soaks up a ton of heat and takes a couple of months to let it all go.”

I immediately knew that sounded a bit too simple. It felt right, but it wasn’t very scientific. So, today, let’s get to the bottom of it.

We all know the summer solstice hits around June 21st. It’s the longest day of the year in the Northern Hemisphere, when the sun is directly over the Tropic of Cancer (23.5°N latitude, near Shantou).

In theory, this is when we…