Why did John Constable make sketches outdoors in the English countryside?

John Constable made sketches outdoors in the English countryside primarily to document the transitory effects of light, atmosphere, and natural phenomena as they occurred in real time. These sketches served several key purposes in his artistic practice:123

• Preparation for Large Works: Constable used these sketches to resolve compositions and capture the immediacy of a scene before developing them into large-scale, finished easel paintings in his studio. He even developed a unique technique of creating full-size oil sketches to plan his major exhibition pieces.12
• Capturing Immediacy: By working outdoors, he could record the "fleeting and dramatic effects" of nature—such as changing skies and meteorological phenomena—with a level of accuracy and luminous quality that he could later evoke in his final works.423
• Personal Connection: Unlike many of his contemporaries who painted popular tourist sites, Constable focused on locations with personal or family connections, such as his native Suffolk, allowing him to meditate on the rural realities of the landscape.45

Through these intensive sketching practices, Constable sought to communicate the physical experience of nature, capturing a sense of passing moments that remained influential for generations of artists.423