HEAT ALERT: Chance of afternoon thunderstorm, extremely hot temps on Sunday for Long Island

Temperatures will feel as high as 110F during the heat wave that starts on Sunday. We will let you know how long the heat lasts and how hot it will get.

Jonathan Cubit

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Jun 21, 2025, 9:38 PM

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Updated 6 hr ago

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WHAT YOU NEED TO KNOW

An extreme heat watch is in effect for Long Island, though Nassau and Suffolk counties are not currently included in the warning.

Heat index values could exceed 105 degrees on Monday and Tuesday, posing a risk of heat-related illnesses.

A thunderstorm is possible Sunday morning, but otherwise, the forecast remains mostly dry through the period.

FORECAST

SUNDAY: Heat wave begins. An afternoon thunderstorm is possible. High temperatures will soar into the mid-90s inland, in the 80s for the beach and east. It will feel like more than 100 degrees.

MONDAY: Record heat possible. Extreme heat is likely. Heat index values could reach 110 degrees with temperatures in the upper 90s. Temperatures near 90 for the beach and east.

TUESDAY: Another record hot day possible. Extreme heat is likely. Heat index values could reach 110 degrees. Temperatures may approach 100 degrees inland. Temperatures near 90 for the beach and east.

WEDNESDAY: Less extreme heat. Hot and mainly sunny. Highs in the upper 80s.

REST OF THE WEEK: More Seasonable. Temperatures return to normal. Highs will be in the low 80s. Rain is not likely.