An incoming polar vortex could sink York temperatures 10 degrees below normal this week.
It's basically the same swirling mass of cold air that had Yorkers shivering over the winter, but it'll have a different effect this time, said AccuWeather meteorologist Carl Erickson.
After a bout of storms at the start of the week, York will see drier air and highs in the upper 70s, Erickson said.
"It'll be below average but actually fairly comfortable for mid-July," he said.
It's uncommon to get this shot of cool, dry air in July, "but it can happen," Erickson said.
Cool summer: AccuWeather data show that high temperatures in July are usually around 87 degrees at York Airport, he said.
So far this month, average temps are almost exactly at the normal mark, but the cooler weather could last until next weekend, Erickson said.
"We'll most likely end somewhat below average for the month of July," he said.
York has had a cooler-than-usual summer: May's temps were 0.9 degrees below average, and June's were 1 degree below average, Erickson said.
He said AccuWeather's long-range forecasters are predicting that August's average temps will be slightly above average.
"Perhaps August might be our warmest period before we head into the fall," Erickson said.
Forecast: Before cooler, drier air moves into the area, Monday and Tuesday will likely bring highs in the mid-80s and some showers and thunderstorms, said Elyse Colbert, a meteorologist with the National Weather Service in State College.
Low temps on those days will be around 70 and 61, respectively, according to the forecast.
The storms will likely roll out by Wednesday morning, and that day's high will be in the upper 70s, she said. Thursday and Friday will have highs near 80.
On those days, humidity will drop and temps will be in the upper 50s at night — very comfortable weather for sleeping with the window open, Erickson said.
York won't see a return to the heat anytime soon: Next weekend's highs will be in the upper 70s and lower 80s, he said.
But considering that the polar vortex is causing fall-like temps in the 60s in Minnesota, Iowa and Wisconsin, the extended reprieve from the heat should feel "refreshing," he said.
— Reach Mollie Durkin at email@example.com.