Why is Beijing so darn hot right now? We looked for answers

Photo: Flickr

Summertime, and the living is challenging

Beijing hit the turbo button today, cranking the thermometer to possibly the highest temperature seen in the city so far this year, and maxing out somewhere between 37 and 41 degrees Celsius, depending on where you get your forecast. (That's as high as 106 Fahrenheit to the Americans out there, and 314 Kelvin to the scientists among you.)

So what happened? Why is it so hot right now? 'Because it is summer,' you may say, and that is a fully acceptable answer, but we want to know more. Why now, why here, and why us? We did a bit of reading to find out just some of the reasons, and here's what we learnt.

Because of our latitude

A large factor for how hot it always is this time of year is our city's latitude on the surface of the earth – around 39° N, if you're wondering – a positioning that Britannica describes as being in 'the major zone of conflict between polar and tropical air masses'. A weather war-zone, no less. Among other factors, this location at the northern tip of the region affected by the East Asian monsoon gives us a climate of extremes that is defined as 'humid continental', with our summer subtype 'hot' and 'monsoonal' (the next three months will see around 75% of our yearly rainfall). That summer is here and it sure is hot, you can feel that much.

Because we live in a basin

Much like this one. Image: Wikimedia Commons

Mountains that surround the outskirts of Beijing from its southwest to its northeast form a semi-circular shield between the city and the steppes of northern China and the Gobi desert, meaning we are left in a basin of sorts. This basin is partly responsible for our often stagnant, windless air, forming a receptacle for the city's pollution, and a relative depression that also keeps the wind out and pollution and heat in during these summer months.

Because we are far from the ocean

Some of the closest ocean to Beijing can be found at Shanhaiguan – and it's got a Great Wall too

In the bigger picture, we are not all that far from the coast, but just far enough away to not receive much of the benefit of a regular, cooling sea breeze. But hopefully you have AC breeze nearby, or a big old fan wherever you are today – if not, check out our guide to some of Taobao's best hot weather solutions to help you beat the heat.

Because of each other

We live in a city of an estimated 22 million people, and in central Dongcheng district, population density is around 23,000 humans per square kilometre – almost the same number as at that hellish crossing in Sanlitun. Sure, all those people breathing on you isn't pleasant, nor cooling in any way, but it's more about what people bring with them to the urban habitat – buildings, roads, machinery, vehicles, more roads and other dark-coloured, concrete things that absorb heat.

Cities around the world suffer from this, a relative temperature increase compared to their surrounding areas, in an effect known as the 'urban heat island', as Smithsonian taught us. It's largely caused by the replacement of plants and green surfaces by concrete. Beijing's actually pretty green – around 42 percent is covered by forest, apparently – but if you're in a built-up area, it's going to feel noticeably hotter.

Because it's a little polluted

Not this bad, luckily.

We've seen an AQI rating around the 100 mark this week, and as is a basic fact that we learn about climate change, air pollution traps solar energy in the atmosphere. Sunlight combining with certain air-based compounds also has the effect of producing hazardous ozone, and we've supposedly experienced a spike in those levels today, as the SCMP reports. Pollution can make temperature worse, and temperature can make pollution worse – the forces of evil combine.

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