A heat advisory is in effect until 9 p.m. Tuesday night.
The National Weather Service issued the alert as temperatures are expected to reach around 90 degrees with a heat index making it feel like the upper 90s.
A heat advisory is issued when the combination of heat and humidity is expected to make it feel like it is 95 to 99 degrees.
“Extreme heat can cause illness and death among at-risk population who cannot stay cool,” the NWS advisory states. “The heat and humidity may cause heat stress during outdoor exertion or extended exposure.”
The oppressive heat is expected to break mid-week with temperatures in the low-to-mid-80s forecasted for Wednesday and Thursday.
Riverhead Town issued a weather advisory and said town beach facilities will remain open until 7 p.m. Tuesday. The town senior recreation center on Shade Tree Lane in Aquebogue will be open as a cooling center until 4:30 p.m. Tuesday.