The internet is not magic. It arrives at your door thanks to copper wire, submarine cables and data centres the size of rugby fields.
These cavernous buildings, stacked with computer servers, underpin every email you send and every online video you watch, and they are subject to the same capricious summer weather as the rest of us.
Internet provider iiNet experienced this in 2015, when multiple system failures knocked one of its Western Australian locations offline as temperatures soared.
Such shutdowns are uncommon, but for those who run our internet infrastructure, managing hot air, humidity and particles is a year-round affair.
All that hot air
The servers that support your apps, from photo sharing to online banking, all need air-conditioning to keep from getting too hot — and not only in a heatwave.
These powerful computers also produce a considerable amount of their own heat.
Mark Ebert is the technical solutions manager at temperature technology company STULZ Australia, where he helps manage cooling systems for data centres, labs and hospitals.
Maintaining the right temperature and humidity in such important buildings is a very different project to the average office space, explained Mr Ebert, referring to the latter as "comfort cooling".
An office typically needs cold air for less than half the day, but a data centre needs it all the time.
This puts more stress on the cooling equipment and consumes considerably more power, although the technology is increasingly resilient.
Adam Gardner, general manager of data centres at Vocus, said that current servers can handle a lot more heat than they did in the past.
"Maybe 20 or 30 years ago, when computers had tape and even punch cards prior to that, the temperature range had to be very, very narrow," he said.
"Where previously it might [need to be kept between] 20 to 24 degrees, now you might be looking at, say, 16 to 27 degrees — a much wider window."
Creating cold corridors
In 2017, most data centres are built to withstand a considerable range of weather and temperatures, but some older sites are still just "big sheds", according to Mr Ebert.
If they don't have much insulation, the cooling system must work overtime to manage the hot air produced by the servers, not to mention scorching summer days.
"One of big challenges you have, if you're mixing air all the time, you essentially have warm air [everywhere] rather than cold air where you want it," Mr Gardner said.
That's why a lot of new buildings practice a heat management system called "containment".
Rather than having one large airspace where cold air mingles with the heat created by the servers, cold air is now maintained in a corridor at the front of the computer. A warm aisle sits at its back where the heat is exhausted.
"You contain the cold or hot aisle so the cold air can't go anywhere but in on to the computer equipment," Mr Ebert explained.
Earth, air and water
Data centres consume a lot of power, not only to run servers but also to keep their climate management systems turned on.
Some estimates suggest data centres take up around 2 per cent of power in the US. In Australia, the Energy Rating body said data centres consumed 3.9 per cent of electricity in 2013.
To cut down, a number of companies are experimenting with more efficient systems.
One option is simple: opening louvres so external air can be run through the building when the outside temperature is acceptable.
This brings up air quality issues, however. Mr Gardner said his systems constantly screen for smoke and particles.
Some data centres are built underground to make cooling easier.
Google, meanwhile, claims its facility in Finland pumps cold sea water through the building, eliminating the need for artificial cooling, but such solutions aren't available to the typical IT company.
Of course, in Australia, summer brings fire as well as heat. Most data centre operators have thought through that, too.
"Not only Vocus, but all of the major providers try and avoid 100-year flood plains, try and avoid flight paths," Mr Gardner said.
"Quite a lot of thinking has gone into what could happen, to try and avoid being in those areas."
Always have backup
Anyone who has experienced a summer blackout knows the electrical grid can get overloaded in the hotter months.
For a data centre, losing power could be disastrous — knocking websites offline and shutting down vital online services.
The solution is to have redundancies or backups built into both the power supply and air conditioning system.
For cooling, Mr Ebert said having 20 per cent more air-conditioning units than needed is the benchmark in some centres.
"A site will usually have one or more electrical feeds from the grid, plus they'll have an uninterruptible power supply for the computer equipment," he explained.
Mr Gardner said his team regularly try and "break" the system.
"We're very regularly doing tests to try and simulate air conditioners failing or turning the power off and trying to make it fail in a controlled manner," he said.
"So that when the power does fail on Christmas day, we know it's going to work."