Since 1895, Lancaster County has warmed 50% more than the continental U.S. average, according to data compiled by the Washington Post.
Lancaster County's temperatures rose about 2.7 degrees Fahrenheit (°F), versus 1.8° F for the U.S. as a whole, the Post's report using federal data shows.
Temperature increases in surrounding counties range from 1.98° F in Berks County to 2.7° F in Chester and York counties.
Using federal data, the Post computed temperatures for every county in the lower 48 states for an article on the regional effects of climate change published this week.
Titled "2° C: Beyond the Limit," the Post article describes "hot spots" where average temperatures have already risen 2° C or more.
One is Lake Hopatcong, New Jersey, where workers once harvested 2-foot-thick blocks of ice in winter. These days, the lake freezes typically freezes in January rather than November, and usually not sufficiently for ice-fishing contests to be held safely.
"These hot spots are chunks of the future in the present," marine scientist Daniel Pauly told the newspaper.
The article attributes regional variations in warming to a variety of complex causes, including urban heat effects, air pollution and atmospheric and ocean currents.
The data indicates the Northeast is warming "especially fast," the Post says.
In New Jersey, that has led to longer seasons for mosquitoes and other insects. At Lake Hopatcong, warm weather and fertilizer runoff are combining to intensify the growth of aquatic weeds and algae.
In Pennsylvania, climate change is expected to lead to, among other things, more frequent and more dangerous heat waves, more intense storms, winters that are predominantly rainy rather than snowy and an increase in plant diseases and pests.