How different one variety is from another. New Yorkers and especially Glaciers are setting very well ... on my Glaciers some of the fruits are almost ripe and most of the flowers have set.
However, some of my varieties, especially Garden Pearl and Tumbling Tom seem reluctant to set. Lots of flowers dying away but no pea-like fruit yet ... maybe I shall see something soon.
Day and night time temperatures need to even out a bit for flowers to to set although there are not as many friendly flying insects around in my garden this season to help pollination.