The variety of each veg varies throughout the year and the no less true for cucumber.
Sometimes big and smooth, sometimes ridged and dark green, some sweeter, some firmer. You certainly get a country garden-grown feel when the variety of cucumber alone is so varied, and because you wouldn't find this breadth of variety in a supermarket it all lends to the appeal of the veg coming from local growers.
Of course, whichever variety of cucumber is ripe in a particular month the quality is always top-notch and the flavour excellent.