The National Weather Service Says Southeastern Pennsylvania had a heat wave over the five-day period ending Sunday. The official temperature in Philadelphia was 90 degrees or higher each day.  It peaked at 93 on Sunday, and the overnight lows for the same period were at 70 degrees or more.  The weather service says an early-season heat wave increases the odds of above-average summer temperatures, and it might also make older people better prepared to withstand later heat waves.