Only clouds that are tall with big water drops can make rain, but they also stop most of the light, which makes them look grey.
Marcella Cheng/The Conversation
To answer this question from Fiona, age 6, we need to know some things about clouds and light.
A storm damaged car abandoned on a roundabout in Bracknell, Berkshire.
At the time, their existence was unknown.
A tornado in the town of Sonnac, France, in September, 2015.
European tornadoes may not come along as often as their US counterparts but they are a real threat and need to be taken seriously.
Tampa residents take a rare chance for a stroll on the seabed.
Pictures of ocean bays emptied of water as Hurricane Irma moved through the Caribbean and Florida show that storm surges can move away from the coast, as well as onto it.
The rainfall from Harvey has now exceeded the amount from the previous record-bearer, Tropical Storm Amelia in 1978.
AP Photo/Charlie Riedel
An expert in extreme weather events explains why the rain – and thus flooding – associated with Hurricane Harvey has been 'unprecedented.'
Hiscox and students practice for the big day with a weather balloon.
Meteorology researchers across the country are prepping experiments for the mini-night the eclipse will bring on August 21 – two minutes and 36 seconds without the sun in the middle of the day.
The stereotype of the conventionally attractive female weather reporter is alive and well on Australian television.
The weather segment at the end of news bulletins has stuck to a familiar format for more than 50 years. But the question of who should actually present the weather has been in a constant state of flux.
Cyclone Debbie looms over Queensland on Monday afternoon March 27.
The category 4 cyclone - the fifth storm of this year's season, and the strongest so far - has buffeted the Queensland coast across a wide area centred on Airlie Beach.
Salisbury Cathedral from the Meadows. John Constable, 1830-1.
Why a mysteriously placed rainbow made perfect symbolic sense – and how weather experts knew the exact date that it appeared.
Get ready for heavier rain.
As the planet warms, the amount of moisture in the atmosphere is increasing. This will cause a lot more heavy rainfall, even in areas that are becoming drier.
Very powerful, try to avoid.
Lightning strikes are powerful – but we haven't had solid estimates of their energy until now. Researchers turned to the hollow stone tubes they create by vaporizing sand for more precise calculations.
Cape Grim, on the northwest tip of Tasmania, is exposed to some of the cleanest air in the world.
CSIRO/Bureau of Meteorology
Cape Grim's air pollution station has recorded some of the biggest changes to the world's atmosphere over the past 40 years.
Damage from Hurricane Matthew in North Charleston, South Carolina, October 2016.
Conservative commentators accused government officials last week of hyping risks from Hurricane Matthew. A meteorologist explains why this is impossible in the internet era.
Chris Mole / shutterstock
Will 2017 be a 'bbq summer'? It depends on changes in the jet stream.
Nice day for the beach. In fact there have been rather a lot of those in Sydney lately.
Natalia Montes de Oca/Wikimedia Commons
Sydney is in the process of smashing the record for the longest run of days above 26℃. Weather, El Nino and climate change are all playing their part.
Drought is a quintessentially Australian experience, yet many of us don’t properly know how they form.
AAP Image/Caroline Duncan
High temperatures make droughts worse, right? Wrong: it's the other way around. Ahead of an El Niño summer that looks set to bring drought to much of Australia, here's a quick primer on how they form.
Storm clouds for California?
El Niño explained: how it works, what a mega El Niño this year could bring and how global warming might affect future El Niño-driven weather patterns.
Even another 85 years of global warming won’t stop the odd cold, snowy winter.
Andy Rain / EPA
While global warming will continue, it's important to assess variability as well as long-term average climates.
Keeping cool as Paris sees its hottest temperatures in six decades.
Etienne Laurent / EPA
Shifting air currents high up in the skies can have a big impact down on the ground.
It’s hot – but some people aren’t too bothered.
Andy Rain / EPA
Parts of the UK are sizzling thanks to Iberian air.