It's premature to call it summer's last gasp. But there is a definite change in the rhythm.

Morning traffic is heavier. The Oakland bars and pizza joints are busy again. There's only a handful of kids, most of them preschoolers, getting soaked in the fountain at PPG Place.

The summer heat drags on, impervious to the back-to-school pace and the flip in the calendar from August to September. After a string this week of highs in the 90s, the crisp, cool fall seems a long way off. Nevertheless, nights have been good for porch sitting, with a sweetness on the breeze while tree creatures buzz and whir the neighborhood to sleep.

There is still plenty of summer to savor. A three-day weekend, for one thing (Labor Day, you know). The county pools at Boyce, Settler's Cabin and South parks will be open for the last hurrah. Local farm markets are still flush with tomatoes, peaches and corn.

Yet a shift is in the air.

The Pitt Panthers line up for football tonight -- another diversion from the Pirates, who have 29 mostly painful games to play. A bumper crop of mums fills every nursery and garden center (colorful, but who wants to plant in such heat?). And gasoline prices are easing off their summer peak, though not so many are doing long trips now.

These are days of transition, what we supposedly prize in the temperate zone. San Diego can keep its year-round 72 degrees. Here in Pittsburgh we get change.

Cartoonist Rob Rogers does "Rob's Rough," an early look at his work and his creative process, exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.