I think the judge was referring to artistic choices made in Ulysses; that JJ's choice of season was spring and choice of locale was "Celtic", just as "his setti

I think the judge was referring to artistic choices made in Ulysses; that JJ's choice of season was spring and choice of locale was "Celtic", just as "his setting", in Ulysses, was Dublin. "His season was spring" is a shorthand was of saying "his chosen season was spring".