A Royal Air Force mobile meteorological unit during World War II (Imperial War Museums via Getty Images)

Nobody likes it when the weather forecast is wrong.

Being caught without an umbrella or towing one around needlessly sometimes sees meteorologists and their profession criticised.

But experts in this field say the current state of weather forecasting and the fact that it is often correct is actually a marvel of science, mathematics and technology.

And it's something that's been millennia in the making.

'Reading' the sky

Humans have tried to predict the weather since ancient times.

Over tens of thousands of years, Indigenous Australians developed an intricate knowledge of seasonal changes in the weather. For example, the Jawoyn in northern Australia recognise five distinct seasons: Jeyowk, Bangkarrang, Malapparr, Jungalk and Guran.

Around 650 BCE, there are records of the Babylonians attempting to predict short-term weather movements by observing the clouds and astrological signs.

Then around 340 BCE, Greek philosopher Aristotle wrote Meteorologica, a treatise where he discussed weather and climate. Some of his ideas were correct (observations about the Earth's hydrologic cycle), but many others were not (earthquakes being caused by winds trapped in the earth).

From these times onwards, there's evidence of many other civilizations trying to divine the weather, especially via "reading" the sky to work out the next day's weather.

Richard Whitaker, a meteorologist who worked at Australia's Bureau of Meteorology for 30 years, says this was often informally codified through weather sayings.

"[People] had all these sorts of sayings to help them predict what was going to happen … A famous one is 'mares' tails and mackerel scales make tall ships take in their sails'," he tells ABC RN's Rear Vision.

"The 'mares' tails' is a cloud formation we [now] call cirrostratus and the 'mackerel scales' are what we [now call] altocumulus clouds — both those sorts of clouds are associated with approaching cold fronts."

Altocumulus clouds resemble 'mackerel scales' (Wikimedia Commons)

A cold front can mean a heavy storm, hence it's a good idea for ships to take in their sails.

But this was all very far from an exact science.

Technological developments

As the centuries ticked over, different instruments were invented that became vital in weather forecasting.

In the 16th and 17th centuries, several European scientists (including Italian Galileo Galilei) developed increasingly reliable thermometers. Also around this time, Italian Evangelista Torricelli invented the barometer, which could measure atmospheric pressure.

But Professor Kristine Harper, an earth sciences historian at the University of Copenhagen, says scientific weather forecasting only really started to develop in the 19th century.

"We see the first scientific weather forecasting in the 19th century … [People] were recording temperature and pressure, because that was basically all they had equipment for. [Then] there were attempts to systematise it … To see if they could figure out what the weather was going to be for the next day," Professor Harper says.

She says one big reason for this was the growth of naval and commercial shipping, as "people who are aboard ships really need to have a sense of what the weather's going to be."

In the early 19th century, British Royal Navy officer Sir Francis Beaufort developed the wind force scale to classify wind speeds. Then following a major shipwreck off the coast of Wales in 1859, Beaufort's protégé Robert FitzRoy was the first to make daily, public weather predictions, which he called "forecasts."

Around 450 people died when the Royal Charter ship sunk in a storm - prompting the start of daily, public weather forecasts.(Wikimedia Commons)

But meteorologist Mr Whitaker says around this time, "one of the big moments [in the history of weather forecasting] was not really connected with the weather at all."

He says the invention and development of the electric telegraph in the 1800s meant weather data and information could be gathered and shared quickly.

For the first time, humans could observe weather systems moving from one location to another in real time.

Understanding the weather

Neville Nicholls, an emeritus professor at Monash University's School of Earth Atmosphere and Environment, says the work of these early forecasters was admirable, but "it was really just about extrapolating the movement of storms."

"They didn't really understand anything about why the storms were moving the way they were," Professor Nicholls says.

He says this changed thanks to the work of Norwegian meteorologist Vilhelm Bjerknes and his colleagues in the early 20th century, who "worked out the equations that govern the development and movement of systems in the atmosphere."

He says Mr Bjerknes gave the world a way "to use mathematics and physics to actually solve how the atmosphere was working at a particular time and forecast how systems would develop."

And forecasters today are still using these same equations.

"They're what we call the primitive equations, not because they're simple, but because they underlie everything," Professor Nicholls says.

'Really helped out by World War II'

Throughout human history, war and conflicts have spurred unexpected technological progress. This has included weather forecasting.

"Numerical weather prediction, quite frankly, was really helped out by World War II," Professor Harper says, pointing to three big developments.

During World War II, thousands of people were trained and worked in meteorology (Imperial War Museums via Getty Images)

"Because of the war, there were a lot more weather observations that were taken and a lot more stations that were set up in areas that had not had coverage in the past … [So] we had massive amounts of data that were available that had never been available before," she says.

"The second thing was because there were so many planes involved during the war, there was a massive effort to train meteorologists."

Professor Harper says there were only 350 meteorologists in the US prior to the war. During the war, more than 7,000 meteorologists were trained.

And she says "the third piece was the development of digital computing", which made solving meteorological equations a lot easier.

Space changes everything

After World War II came the development of weather satellites. This was a game changer as it allowed meteorologists to track things like the development and movement of storm systems.

"Satellites started to increase the amount of data we had about how the atmosphere was looking at any particular time …. [Up to today] where we now get millions of observations every day from satellites," Professor Nicholls says.

"Looks like the trade swell will keep the Queensland points busy for a few days, so get on it, Squidlips"

The end of World War II also saw the creation of the United Nations and, with it, increased international cooperation on some issues.

One of the UN's new agencies was the World Meteorological Organization. It established a global system for observing, analysing and forecasting meteorological conditions, called World Weather Watch.

"Very large resources [were put] into the development of a global network of satellites and strengthening the other global observing systems, including drifting buoys in the Southern Ocean," says John Zillman, a meteorologist and former president of the World Meteorological Organization.

Equations solved by supercomputers 

Weather forecasting today is a culmination of all of those scientific, mathematical and technological developments.

As Professor Nicholls explains, there are now "thousands of points across the atmosphere, across the globe" that humans are monitoring for weather purposes, "from the [Earth's] surface to kilometres above the surface."

At these points, information is recorded, including temperature, pressure, air density and the wind movement.

"We put all of that together and solve, basically, seven equations. We solve them all simultaneously across the world, at all these levels. And the only way we can do that is by massive supercomputers, which do it all at once," Professor Nicholls says.

So do humans still have a role in the process? Professor Harper is clear: "Of course."

"Because we're still the ones that have to interpret the charts … The meteorologists get these charts, they look at them, they discuss what's going on. And then they're the ones that tap up the forecasts."

And from assisting global transport networks and agricultural practices, to life and death situations like cyclones, to whether or not we take an umbrella to work, these forecasts impact our lives every day.

//NICK BAKER & KERI PHILLIPS