Friday was a record breaking 99 degrees in Boston- the hottest day of this current heat wave – the third Boston has seen this season. 

Mayor Thomas Menino recommended staying in the air conditioning for businesses and homes, and he even set up cooling shelters across the city. Forecasters said that the heat and humidity will have reached its peak by Saturday afternoon.

The hundred-degree temperatures have been great news for pools and beaches, but tough on anyone who works outdoors.

At Urban Hound in the South End, head trainer Nick Miller said they've got a fully booked weekend. It’s surprisingly cold inside Urban Hound. Perfect if you’re covered in fur. 

“We have a lot of dogs that need more exercise but they might only just for safety reasons go out for 15, 20-minute walks on a hot day like this," Miller said. "So they can come to this facility here and get a full day of air conditioning. We do see an increase for those types of clients.”

These dogs are living comfortably, that’s for sure. Perhaps more so than their owners- some of whom are running errands. About a half mile away is the Union Park Laundromat and laundry service.

You can’t even see inside the windows, they’re blocked with enormous bags of clothes, sheets and towels. The owner says he’s so busy doing loads and folding, he doesn’t have time to talk to a reporter. But one of his customers does

Sheryl, who lives in the neighborhood, said she can’t stand the heat from washers and dryers in this weather.

“Definitely not when it’s hot," she said. "I honored him on the way out for doing all that great work where I wasn’t even willing to consider doing it. It’s miserable.”

But next door, at the South End Buttery Market, no one seems miserable. Sales of ice cream and iced coffee are through the roof, cashier Emily Mitchell said.

“Now that’s it’s been hot, it’s been busier. People usually come to get their dinners because we have takeout,” she said. 

And it seems that in this weather, people are eating healthier. 

“A lot of people have been buying the black bean and corn salad, just because those are such classic hot-day, barbeque-outside meals. We also get a lot of people buying corn on the cob and the Caprese salad. Meals that don’t have to be heated up.”

But business isn’t booming everywhere. In the shadow of the Prudential Center is a small children’s clothing and toy store called Tadpole, which at this moment is quiet. David Hauck is the owner.

“This week the weekdays have been a little slower. People are dragging a little more. If they have AC at home or at their office they’re probably eating lunch at their desk.”

Hauck says the trick is getting customers in the door. When they feel the air conditioning, they tend to stay longer than usual.