El Nino typically does not have a significant influence on Arizona precipitation until later in the year, particularly the winter. As shown in Tom's most recent post, the precipitation pattern over the Pacific/North America region this past summer was remarkably consistent with the expected El Nino precipitation pattern. Emily wrote about the North American monsoon a couple of years ago, suggesting that there may be a weak relationship between ENSO and the North American monsoon (hence Arizona precipitation in the warm season), but the connection looks pretty weak.