Temp hits big 9-0 for first time; 90s trend bullish

At 3:11 p.m. Thursday, the automated thermometer at Philadelphia International Airport read 90 for the first -- and almost certainly not the last -- time this season.

This might seem early for a 90 reading, particularly given that temperatures this month have been consistently below normal until this week.

But on average Philly's the daily high hits 90 from 1 to 2 times a month, according to National Weather Service records.

With relative humidities low on Thursday, the heat indices were unimpressive. At 3 p.m. when it was 89 at the airport, it actually felt subtly cooler than that: The heat index was 87.

The summery flirtation is due to persist into the holiday, with highs in the vicinity of 90 Friday, Saturday, and Sunday, and higher indices.

The 90s have become more a summer staple here since 1987, paralleling a general increase in the world's temperature.

On average, in the 20th Century Philadelphia has experienced 21 days with highs of 90 or better.

Since 1987, the average has increased to 29.

We are skeptical of longer-range summer outlooks, but we feel safe in saying that this won't be the last 90-degree day here in 2016.