Depends on the year LGA vs NYC. Check 2006 and 2010. Not just Newark but CNJ into NENJ is on a whole a concrete jungle and EWR better depicts the temps there. Im usually more in line with EWR than NYC but tally less 90's than EWR. Wind direction 2014/2015 cleaerly influencing LGA heat potential.
Locking above in for a real # but believe the ranges to be as below. So thinkin on the hotter end of the ranges.
NYC: 16 - 19
EWR: 29 - 31
LGA: 23 - 25
PHL: 33 - 36