In what time period is On Chesil Beach set?

The action of the novel, both past and present, takes place within the two decades (plus a bit) of the mid-twentieth century. The main narrative line - that is, set in the novel's present - takes place in the early 1960's, when England (and arguably the rest of the world) was on the cusp of what history refers to as the sexual revolution. This is significant because the characters, on the one hand, feel that revolution coming: but, on the other, hand and in spite of their impulses, are unable to move into their own acts of sexual revolution because of their histories as individuals and as repressed Britishers. Meanwhile, the sections of the narrative set in the past cover a period of 20 years, from the births of Edward and Florence in 1940 (pre-World War II) and their eventual meeting and relationship, in the late 1950's and early 1960's. This 20 years was marked by significant experiences of repression and entrenchment of social / cultural attitudes towards, among other things, freer expressions of sexuality.