Hundreds of residents took advantage of Montclair’s free pool day on Monday in order to get relief from the heat wave that hit early in the week. Temperatures climbed to 96 degrees, but with a heat index of 105.

Others, not wanting to dive in, headed to the library and the town hall, which were open as cooling centers beginning last weekend.

Around 1 p.m. on Monday, township officials announced the pool would be free of charge from 1 p.m. to 8:30 p.m. Out-of-town residents were still expected to pay the standard rate of $20. But on Tuesday, the pools had returned to their normal operating practice of charging $10-$15 a visit or open to those with valid seasonal badges or to use the pool.

At 7 p.m., Nishuane Pool saw a steady stream of residents. Pool staffer Ida Starr estimated that about 200 people had come to the pool during the day.

“[It was] definitely the busiest during three to four,” said lifeguard Liz Cummings. “We get busy [on a normal day], but it’s usually just the regulars.”

Because the town opened up the pools to everyone, Nishuane saw more patrons coming in from other parts of town, Cummings said. And there were a large number of children coming to use the pool, she said.

At Mountainside Pool, residents headed to the pool for a free dip after work and camp in the early evening hours. Pool staffer Tori Rivera said that a “decent” number of people had come throughout the day.

The Bloom family - Mike, Julie and son Raymond - had spent five hours at the pool on Sunday, and headed back to the pool on Monday immediately after dinner.

“We’ve been using our whole house fan,” Mike Bloom said, when asked how the family was faring during the heat. The upper stories of their Upper Mountain Avenue house had gotten uncomfortably hot during the heat wave. One night, he said, he woke up in the middle of the night, took a shower and went to sleep downstairs where it was cooler.

Over the weekend, nine people took advantage of the AC at municipal building, Communications Director Katya Wowk said.

“Nonetheless, people know that it’s there if they need it,” she said.

Library Director Peter Coyl said that the library always sees a steady stream of people during the summer months. “We haven’t noticed a huge increase from people using us as a cooling center but we are glad to be able to offer the option to anyone who needs it,” he said.

Essex County also opened up a cooling center at the Codey Arena at the South Mountain Reservation complex in West Orange.

As of Monday, the township reported no residents ill from the heat.

There were two reported power outages in Upper Montclair on Monday, in the area of Watchung Avenue and Gordonhurst Avenue. As of Tuesday, there were no reported outages, according to PSE&G’s outage map.

The Montclair Ambulance Unit had not seen an increase in medical calls related to the heat, Deputy Chief Frank Carlo said Monday. He attributed this to people heeding the warnings about the heat and taking care of themselves, which included staying hydrated, limiting outdoor activity, limiting alcohol and caffeine intake, and wearing light-colored clothing.

Daytime temperatures were expected to be in the 90s for the remainder of the week, according to the National Weather Service.