Yesterday's 1.33" of rain in Philadelphia propped the meteorological summer (June-August) total at the Airport to 25.13", which sets a record for wettest summer and wettest season on record with 30 days left to go in August.
It's an impressive record despite it not being completely representative of the region given what happened on Sunday, but this summer has been one where rains have been plentiful for many. While wettest summer ever records may not drop like flies for everyone else around the Mid Atlantic, there will be quite a few top 10 wettest evers by the time we're done.
As you may or may not know, records in Philadelphia on monthly and seasonal climate go back to 1872. If one were to look at unofficial records from earlier weather observers in the city, the summer of 1867 had 29.11" of rain between June and August, with 11" in June, 2.39" in July, and 15.82" in August thanks to two tropical systems (or remnants thereof) that impacted the city with a lot of rain. (Note, the 1867 wettest year mark referenced in the immediately linked article up above was broken by 2011...but as of the original date of the linked article it had not been to that point)
From a National Weather Service perspective, records before 1870 do not count as official since there was no National Weather Service or Weather Bureau as the keeper of meteorological record although many locations have pockets of climatological records going back prior. While records from before 1870 are impressive in some cases, they aren't "official" as far as the NWS is concerned.
That said, Nature has four weeks to ensure that 29.11" mark gets knocked out. A slightly above average but not flood-producing August on rainfall will get us there.