I shall go further back into my records shortly, but must now take Penny her morning tea (and mine).
Update: OK, now I've wandered round my archive, and I see that in 2009 I didn't run the trap at all between 26 April and 23 May because for quite a chunk of that time we were in California and New Mexico. And in 2008, my first year with the moth trap, I didn't get going until 11 June. So my vague feeling that May used to be much mothier is entirely the product of my imagination.
This is a good example of our tendency to think that everything was better in the good old days. By and large, it was not. Don't expect wonders in the immediate future, meanwhile, because the forecast is of cold nights, possibly including frost.