Richard Hammond investigates the crucial role temperature plays in all weather. Without heat, there would be no weather - no clouds, no rain, no snow, no dust storms, no thunder and lightning.Richard sets off to find out about hot air and with the help of a quarry and a massive hot plate discovers just why it is so hard to pull a sword out of snow. He discovers, by building his own massive dust storm with the help of a few friends and dust specialist Dr Nigel Tapper, just how sand from the Sahara bounces its way to the UK.In Canada he creates his own ice storm. He also drops in on Dan Morgan, who creates lightning bolts in his lab, where Richard is able to see thunder and hear lightning with the aid of some special cameras, light bulbs and a few candles.