The worst of this week's hot weather is over, meteorologists said, but what's ahead for Long Islanders is only a modest cooldown.
Sunday's temperatures — which led to an excessive heat warning for northern Nassau County until 6 a.m. Monday — were expected to be the highest of the week, according to the National Weather Service.
Meteorologist David Stark of the weather Service in Upton said the high temperature of 95 degrees at MacArthur Airport in Islip Sunday and the 103 degree heat index, which combines high temperatures and humidity, "made it feel like lower 100s with the humidity.
Monday's high was forecast to be 90 degrees with a heat index in the mid-to-upper 90s, Stark said. The record high at Islip is 99 degrees in 1966.
An islandwide heat advisory expires at 6 a.m. Monday but a new advisory for northern Nassau and northwest Suffolk begins at 6 a.m. and ends at 9 p.m. Monday, he said. An air quality alert will be in effect Monday from 11 a.m. to 11 p.m.
Tuesday's high is predicted to cool down slightly to 88 degrees, Stark said.
The record high for Tuesday was again set in 1966, at 104 degrees in Islip, he said.
"We're not going to be breaking any records for the next few days," Stark said.
Most of the Island will see mid-to-upper 80s on Wednesday, with the East End's temperatures in the lower-to-mid 80s and a high of 80 degrees on the South Shore barrier islands, he said. Ocean breezes along the barrier islands will keep temperatures cooler at the shores.
There is a 20 percent chance of a shower in the late Wednesday afternoon or early evening.
"We're not expecting a washout by any means," he said.
Fourth of July fireworks will likely take place in temperatures of the upper 70s once the sun sets, Stark said.
Stark said normal temperatures this time of year are 81 to 83 degrees islandwide. Peak summer heat is typically in mid-to-late July and early August, he said.
Municipalities were making facilities available for those wanting to escape the heat.
In Hempstead Town, officials extended the hours of pools and beaches for Monday, according to a news release. Cooling centers will also be open. For more information, visit the town's website at toh.li.