The heat is on.

Record-breaking heat is expected in Chautauqua County, and throughout Upstate New York, starting Monday. Here’s what the National Weather Service’s Buffalo office had to say on Friday morning:

“An extended period of hot and humid weather is expected next week. The heat index WILL rise well into the 90s Monday through Thursday, with the hottest days being Tuesday and Wednesday with heat index values in the mid to upper 90s.

“It will not only be the impressive level of oppressive midday and afternoon heat to contend with, but the cumulative impacts of only having the mercury settle only into the lower to mid 70s for the overnights, thereby extremely limiting any relief.”

The weather service forecasts for Dunkirk next week show daytime highs between 87 and 89 degrees, with lows around 72.

Jamestown tends to get slightly hotter days and cooler nights than Dunkirk in the summer — and the forecast shows it again. Tuesday and Wednesday are supposed to top out at a sizzling 93 degrees in Jamestown. Thursday will offer no relief, with a high of 91. Nighttime lows at least will be slightly cooler than by the lake, around 69 degrees all week.