why isn’t June/December the dead hottest part of summer in the northern/southern hemisphere?

Question

It is my (barely informed) understanding that summer is caused primarily by the larger amount of sunlight hitting that hemisphere during the season. So why is it that (in the northern hemisphere) July and August are so often hotter than June (I know it’s not always the case but usually).

Also why wouldn’t May, getting just as much direct sunlight per day as July, be as hot on average as July? Why is August even hot when the end of the month is getting close to the equinox?

In: 3

Answer 1

So, you know how if you put a bowl of water (or other microwaveable soup/similar), in the microwave, just putting it in for 5 seconds isn’t enough to get it boiling hot, despite being microwave amounts of energy being zapped into it? It doesn’t just instantly heat up to boiling because you added a bit of energy to it, a bowl of soup likely takes around 30-60 seconds to get ‘warm’, and another 30-60 seconds to reach boiling, with a microwave.

The reason for that is that there’s a lot of mass (and energy) that goes into changing temperature. Water is one of those things that is, naturally speaking, really difficult to change it’s temperature; it absorbs heat quite a bit more than it radiates heat.

Apply the same kind of idea, just with the sun and the earth. The earth has a lot of mass, and all the time the sun spends heating things up, is also counter-balanced by the angle of rotation the earth has (why we have seasons at all), and how much sunlight, for how long, is hitting each hemisphere at a time. It’s why it isn’t really until mid/late November or December that the northern hemisphere really “feels like” winter temperatures – why it doesn’t feel like “spring has sprung” in the northern hemisphere until around mid/late March or April – why the “hottest of summer” doesn’t feel like it’s a thing until late July and August. There’s a lot of mass to heat up (and/or cooldown), and a lot of thermal energy to move around – it isn’t going to happen instantly, because all that mass is holding on to it – it takes time for that energy to dissipate.