A Shippensburg professor tackles heat island data. He cites temperatures can be 18 to 20 degrees hotter in a downtown urban core like Harrisburg compared to the surrounding countryside.
https://www.fox43.com/article/weather/urban-heat-islands-make-cities-even-hotter-green-infrastructure/521-a04460e4-0424-4e91-bd4b-8f06db4ad685