Constable noted the times of day on his drawings and oil sketches throughout his working life. This watercolour is a splendid example of his late work, reflecting his interest in scientific observation and in particular the optics surrounding the appearance of rainbows. His understanding of rainbows is evident in the way he showed the colours of the outer,  or secondary arc reversed, with red on the inside and blue on the outside, as these would appear in nature (P. Schweitzer, ‘John Constable, rainbow science, and English Color Theory’, Art Bulletin, vol. 64, no. 3, September 1982, pp. 426–27). Constable was also fascinated by the effects of shafts of sunlight, as C.R. Leslie recorded:

I remember that he pointed out to me an appearance of the sun’s rays, which few artists have perhaps noticed … When the spectator stands with his back to the sun, the rays may be sometimes seen converging in perspective towards the opposite horizon (Leslie (1843/45) 1951, p. 282).