Close window
Close window
This section of the new site isn't ready yet. We've brought you back to the current site.

Human Swarm - how weather drives our herd mentality

Human Swarm

31 May 2013 - A new Channel 4 documentary, Human Swarm reveals new evidence that suggests that our collective behaviour is driven by the powerful force of the weather.

The Met Office has the expertise and experience to combine the latest science with ground breaking advances in technology and local understanding to deliver operational advantage to our customers that can help businesses manage risks and opportunities as they arise from our weather and our collective behaviour.

The documentary reveals that one of the most powerful influences on each of us is the temperature, with the smallest changes affecting us physically and psychologically - without us even being aware of it - when the temperature drops, our appetite increases, our mood alters, our buying habits change and our health suffers in many surprising - and surprisingly precise - ways.

This Coldest March for the UK since 1962, leading each of us to demand nearly 20 % more gas and electricity than usual to heat our houses. And when 63 million of us are doing the same thing at the same time the effects multiply.

It's vital that Energy to ensure enough electricity and gas is available immediately. The Met Office has one of the most powerful supercomputers in the world, capable of one hundred trillion calculations per second, which tracks temperature and weather data round the clock, providing detailed forecasts for the whole country, down to less than the nearest mile.

Our swarm behaviour continues when we leave our homes. When the temperature drops below 10 °C we use 43 % more fuel just in the first mile of journeys. The cold makes the oil thicker; the engine needs a richer mix of fuel and air; and colder air in the tyres reduces their pressure and causes more friction. Road services adds up to an extra £1.4 billion to our annual fuel costs.

We eat differently when it's cold too. Sales of porridge soar - Quaker Oats sell 200 % more than normal, 20 million packets each week. Although we all make individual decisions about our breakfast, the overall result is that we act in a very similar way to a swarm.

Very small changes in temperature can have a profound effect on our Health services too. In December 2012, with the temperature regularly below freezing, visits to outpatients clinics shot up by 669,000 compared to the previous quarter. And analysis of 84,000 hospital admissions reveals that for each drop in the temperature of just one degree there were an additional 200 heart attacks.

Industry services to run their businesses effectively. Combined with their sales figures the results can be extraordinary - when temperature changes dramatically they know what we want to buy even before we do.

At Morrisons' 1.2 million square foot distribution centre in Yorkshire, the biggest in the UK, the supermarket's ordering system uses five years' sales and weather data to predict what we will want to eat and automatically select the right food to its stores.

Over this Easter weekend, the coldest on record, sales of pies were nearly 250 % above normal. But, more surprisingly, cat litter sales were 15 % higher, because our cats stayed inside. And sales of dishwasher salt went up by 138 %, not because we have dirtier dishes, but because we think - completely wrongly - that it will clear our drives.

Likewise, when the temperature rises, we can be equally predictable. With three days of warmer weather, and the mercury hitting a 'magic' 18 °C, stores know we will all decide, quite independently, to have a BBQ. Retail, Morrisons divert from producing beef mince for casseroles to make burgers - distributing up to 1.2 million burgers per week, as well as the accompanying salad, buns and beer.

On weekend of April 20th this year, when the temperature reached 18 °C for the first time in 2013, online search for DIY items rose by 50 % from the previous day and searches for mountain bikes doubled. There was also a 50 % increases for the word 'pub' and a 54 % rise in searches for tanning salons.

"We are at the dawn of a data revolution - the amount we produce in our daily lives is increasing," says Jimmy Doherty. "I can totally understand why this can all seem a bit disturbing - that everything we do is now stored as data - but when all this information is matched with the weather data it really does increase our understanding of our behaviour - as a human swarm."

You can watch 'Human Swarm' on 4oD catch up service until 28 June 2013

Last updated:

Follow us on

Facebook, Twitter, YouTube, Instagram, Snapchat, or LinkedIn Facebook Follow @metoffice on Twitter YouTube Instagram Snapchat LinkedIn