Constable believed that depicting the sky was one of the most difficult parts of landscape painting – and one of the most important. He thought that skies should ‘sympathise’ with their subjects.

During 1821 and 1822, Constable made numerous cloud studies at Hampstead, on the outskirts of London. He painted clouds day after day – often several times a day. He worked quickly, sketching many of them in about an hour.

On his sketches, Constable recorded the date, the time of day, and information about the light, wind, temperature, and humidity. He noted the weather conditions before and after he made his paintings. He was interested in movement – in changing conditions and the shifting effects of light and shade.

Constable categorised clouds. More significantly, he showed the sky as being infinitely variable  – ‘the realm over which man has no control’.