Atlantic depression stuck over the Purple Empire. No chance of any butterfly activity there, let alone emergence, until the wretched thing fills... Even then, iris is unlikely to emerge until after a couple of warm sunny days.
We had seasons like this during the late 1970s / early 80s, and they were hell on earth. Here are the start dates for iris in Alice Holt Forest, Hampshire, during the sequence of wet summers from 1977 - 1981, with start dates for camilla and paphia for comparison. Interesting that the latter two tended to emerge much later during that period than has been the case in recent years, including 2012.
iris camilla paphia
1977 23rd July 10th July 12th July
1978 15th July 25th June 7th July
1979 15th July 11th July 6th July
1980 20th July 5th July 29th June
1981 18th July 12th July 7th July