50 Fun Facts About Weather and Climate

In which month does Earth reach perihelion, the point in its orbit closest to the Sun?

January is perihelion, so Earth is nearest the Sun in the middle of the northern winter; the seasons come from the tilt of the axis, not from distance.

Which gas causes about half of Earth's greenhouse effect, more than carbon dioxide?

Water vapour is the most important greenhouse gas overall, responsible for 41–67% of the effect, but it acts as a feedback to other gases rather than a driver.

Without its greenhouse effect, Earth's average surface temperature would be about what, instead of roughly 14 °C?

Minus 18 °C is colder than a home freezer, and the roughly 32-degree gap is heat trapped by the atmosphere's absorbing gases before it can escape to space.

Which continent, the coldest, driest and windiest, is a polar desert with only about 150 mm of precipitation a year?

Antarctica gets its scant moisture almost entirely as snow, yet over millions of years that trickle has built an ice sheet kilometres thick.

Which Swedish astronomer's temperature scale first ran backwards, with 0 for boiling water and 100 for freezing?

Anders Celsius died in 1744, and it was the botanist Carl Linnaeus who flipped the scale the following year so that bigger numbers meant hotter.

The louvred white box that shelters thermometers at weather stations was designed by the father of which novelist?

Robert Louis Stevenson's father Thomas was a Scottish lighthouse engineer whose double-louvred screen, reported in 1864, still sets the standard for air temperature readings.

Which HMS Beagle captain on Darwin's voyage later ran Britain's weather office and coined 'weather forecast'?

FitzRoy was pushed into forecasting by the 1859 wreck of the Royal Charter, and the first daily forecasts appeared in The Times in 1861.

Which MIT meteorologist's 1972 talk asked whether a butterfly flapping in Brazil could set off a tornado in Texas?

Edward Lorenz spent his whole career at MIT, and the famous title was coined by a colleague, Philip Merilees; an earlier version of the image used a seagull's wings.

Guabancex, goddess of the 'juracán' storms behind the word hurricane, belonged to which Caribbean people?

The Taíno were aware of the spiralling wind pattern of hurricanes, and the word made an early English appearance in Shakespeare's King Lear.

Since 1958 the Keeling Curve of carbon dioxide has been measured at an observatory on which Hawaiian volcano?

Mauna Loa's record, begun by Charles David Keeling, wobbles every year as Northern Hemisphere plants take up carbon dioxide in summer and release it in winter.

Which atmospheric layer holds the ozone layer and warms with height as that ozone absorbs the Sun's ultraviolet?

The stratosphere is heated by the rapid breakdown and re-formation of ozone, producing a temperature inversion that acts as a lid on the weather below.

Which atmospheric layer, the coldest place on Earth at around -85 °C, is where most meteors burn up on entry?

The mesosphere runs from about 50 km up to the mesopause near 85 to 100 km, and re-entering satellites break up in the same layer as the shooting stars.

Which French scientist's 1835 paper on water wheels expressed the force that bends Northern Hemisphere winds rightward?

Gaspard de Coriolis was studying water wheels, yet the rightward swerve he quantified is what sets winds spiralling around every storm and ocean gyre.

Deserts lie under the sinking air of which circulation cell, named for the lawyer who explained trade winds in 1735?

The Hadley circulation's descending branch sits roughly over the 25th parallel in each hemisphere, which puts the Sahara and the Kalahari under dry, sinking air.

Sailors gave what name to the windless belt where the two hemispheres' trade winds converge near the equator?

The doldrums are the Intertropical Convergence Zone, whose monotonous windless weather could leave a sailing ship becalmed for days on end.

Which calm belts around 30° north and south are named, legend says, for what becalmed sailing ships threw overboard?

The horse latitudes bring sunny skies, calm winds and very little rain, and ships stuck there ran short of water for the horses they were carrying.

Which warm, dry downslope wind in the lee of mountains has a German name that also means 'hairdryer'?

Föhn air heats up by compression as it pours down the lee slopes, which is why Alpine valleys can turn springlike in the middle of winter.

Lines of equal pressure on a weather chart, whose name comes from the Ancient Greek for weight, are called what?

Isobars packed closely together mean a steep pressure gradient and strong winds, which is how a forecaster reads a gale straight off the chart.

On a weather map, a blue line with triangles pointing the way it travels marks which boundary between air masses?

A cold front is where dense cold air wedges under warm air and forces it up into a narrow band of showers; a warm front is drawn with red semicircles instead.

In the Northern Hemisphere, winds around which pressure system rotate clockwise, typically bringing clear skies?

An anticyclone is a high, with air sinking and spreading outward, and in the Southern Hemisphere the same kind of system spins anticlockwise.

Which dense, towering cloud, named from the Latin for swell and cloud, is capped by a flat anvil-shaped top?

Cumulonimbus tops flatten into an anvil where the rising air hits the equilibrium level near the tropopause, and the shelf can run out kilometres ahead of the storm.

Which high-altitude clouds made of ice crystals take their name from a Latin prefix meaning tendril or curl?

Cirrus clouds sit high enough to be made entirely of ice crystals, and their fibrous streaks are combed out by the strong winds aloft.

Which dark-grey layer cloud, its prefix Latin for a rain-bearing cloud, brings continuous rain but never thunder?

Nimbostratus is a multilevel, amorphous, nearly uniform sheet that rains over a wide area, with no lightning or thunder at all.

Which saucer-shaped clouds, forming in standing waves on the leeward side of mountains, are often mistaken for UFOs?

Lenticular clouds hang still while the wind blows straight through them, because they mark the crest of a wave in the airflow rather than a parcel of air.

What term, Latin for a rod or twig, names shafts of precipitation that evaporate before they reach the ground?

Virga is also called a dry storm, and its trailing streaks below the cloud base are common over deserts, where the air beneath is too dry for rain to survive.

Which kind of rainfall, heavy on India's Western Ghats, falls where air is forced up and over rising terrain?

Orographic rain leaves the far side of the range dry, because the air warms and dries as it descends the lee slope, creating a rain shadow.

Air cooled at constant pressure and moisture to which temperature reaches 100% relative humidity?

The dew point equals the air temperature when relative humidity hits 100%, which is why mist and droplets form on clear, calm nights as the ground cools.

Plants lose 97–99% of the water they take up through which process, as it evaporates from their leaves and stems?

Transpiration pulls water up from the roots like a wick, and most of what a plant drinks simply passes through it into the air.

After evaporating, a water molecule stays in the atmosphere roughly how long before it falls again as precipitation?

About 9 days is the average residence time, so the atmosphere's entire stock of moisture is swapped out roughly 40 times a year.

Of all the water on Earth, roughly what share is fresh rather than salt, with most of that locked up in ice?

2.5% is the fresh share, and nearly 70% of it sits in glaciers and ice, leaving only about 0.3% of freshwater as liquid on the surface in lakes and rivers.

Which Russian-German climatologist behind the letter-coded climate scheme was Alfred Wegener's father-in-law?

Wladimir Köppen first proposed his system in 1884, and his student Wegener, later famous for continental drift, married his daughter Else.

In the most widely used climate classification, group A, with every month averaging at least 18 °C, has which name?

Tropical climates in the scheme also need significant precipitation, and the other four groups, lettered B to E, run from arid through temperate and continental to polar.

Dry summers and mild winters link Greece, California, South Africa's southwest tip and which South American country?

Chile shares the pattern on its Pacific coast, as do Perth and Adelaide in Australia and the Atlantic corners of Portugal and Morocco.

Which biome of pines, spruces and larches, the largest on land, spans Canada, Sweden, Finland and most of Russia?

The taiga is also called the boreal forest, and it reaches as far south as Hokkaido in northern Japan and the northern fringe of the contiguous United States.

Fresh snow reflects about 0.9 of the sunlight hitting it; what term names the fraction of sunlight a surface reflects?

Albedo for Earth as a whole averages about 0.3, so nearly a third of incoming sunlight bounces straight back to space without warming anything.

India dates its monsoon onset to 1 June, when rains 'burst' onto the coast near Thiruvananthapuram in which state?

Kerala gets the rains first because the southwest monsoon sweeps in off the Arabian Sea, and the English word monsoon itself comes from the Arabic for season.

East Asia's early-summer rains are named for which fruit, whose ripening south of the Yangtze was said to cause them?

Plum rain falls along a persistent stationary boundary between air masses, and tradition held that moisture evaporating from the ripening fruit turned into the rain.

Which English physicist, India's director general of observatories from 1904, described the Southern Oscillation?

Gilbert Walker was hunting for a way to forecast the Indian monsoon, and the Pacific-wide circulation he uncovered is now named the Walker circulation after him.

When El Niño weakens the easterly trade winds and warm water surges east, which country's anchovy fishery collapses?

Peru's anchovy crashes followed the El Niño events of 1972–73, 1982–83, 1997–98 and 2015–16, because the warm water shuts off the upwelling of nutrients.

Which semi-arid belt along the southern edge of the Sahara takes its name from the Arabic for 'coast' or 'shore'?

The Sahel is the transition zone between the drier Sahara to the north and the more humid savannas to the south, stretching from Senegal to Sudan.

The four-cup anemometer for measuring wind speed was invented in 1845 at the observatory of which Irish city?

Armagh Observatory's Rev. John Thomas Romney Robinson mounted four hemispherical cups on horizontal arms, a design still spinning on weather masts today.

Swiss scientist Horace-Bénédict de Saussure's hygrometer used a stretched strand of what, which lengthens in damp air?

Human hair is hygroscopic, tending to hold on to moisture, so its length shifts with humidity by enough to move a needle across a dial.

The Cheugugi of 1441, the first standardised rain gauge, appeared under Sejong the Great in which country?

Korea's Joseon dynasty issued the gauges so rainfall could be measured the same way across the kingdom, and Sejong is the same king who created the Hangul alphabet.

In 1930 Pavel Molchanov flew an early version of which balloon-borne instrument, which sends its readings to the ground?

Radiosondes are battery-powered telemetry packages carried aloft by weather balloons, and they still supply the upper-air profiles that forecast models are built on.

Which room-sized 1940s computer produced the first weather forecasts by machine in 1950?

ENIAC's forecasting team included Jule Charney and John von Neumann, and the run rested on a highly simplified approximation to the atmosphere's governing equations.

Which English mathematician imagined in 1922 a vast theatre-like hall of clerks computing the weather by hand?

Lewis Fry Richardson's own trial forecast took him at least six weeks of hand arithmetic, which is why he dreamed of thousands of people calculating in parallel.

Which Victorian polymath, remembered for fingerprints and 'eugenics', made the first weather map printed in The Times?

Francis Galton's map ran on 1 April 1875 and showed the weather of the previous day, 31 March, rather than any forecast of what was coming.

Forecaster James Stagg's prediction of a brief break in the weather let which 1944 invasion go ahead a day late?

D-Day had been pencilled in for 5 June, but high winds, heavy seas and low cloud on 4 June made launching landing craft and finding targets from the air impossible.

Early weather observations underpin 'Meteorology', a treatise written in 350 BC by which Greek philosopher?

Aristotle's title comes from the Greek metéōros, which also gives us the word meteor, so shooting stars and the weather share a root.

Which country's 1922 reading of 57.8 °C at 'Aziziya held the world heat record until the WMO decertified it in 2012?

Libya lost the record in 2012 after investigators concluded an inexperienced observer had probably misread a new instrument, handing the title back to Death Valley.