NYC to Ireland for $699, Including Tax
Having paid about $1,000 for the same flight (but with a different airline) I have to admit this is a good deal and a good time to go to Ireland too.
When friends got married in Northern Ireland (right on the Irish border) they were told that weather there is usually best (read: not rainy) in June or September. (though - honestly - even in early September for their wedding it was a bit rainy so there probably is not definite "rule" about Irish weather)
This Aerlingus deal - good through May 30 - includes all of September.
I know folks around here are proud of their Irish heritage and Ireland is an amazing place to go. So go.