I would hold off a few more weeks as they always have a summer sale in March. Would think once this offer is over they will have seats reduced after 15 June
I would seriously not recommend that in regard to US Travel. Quite the opposite of Europe, Aer Lingus flights to the US especially in July and August don't get much cheaper then €300 each-way inc taxes/charges. My cousins in St Louis come to Cork every July, the 4 of them usually pay upwards of $6k for return flights to Dublin via Chicago with Aer Lingus/United.