Neither rain nor sleet nor snow keeps Paul Carlson from showing up for his job. Clients named Callie, Gracie, Booger, Scarlett, Scout and others eagerly look forward to his daily visits, and if Mr. Carlson fails to make his appointed rounds, there could be some "accidents" inside the house.

Since this is a pet column, you can guess what kind of accidents I'm talking about.

Mr. Carlson, 26, of Shadyside, is a professional dog walker who handles many of the midday clients for PetSitPgh. Dog lovers might think he has a dream job, and, for the most part, he does. But the weather is a factor for him and the scores of other professional dog walkers in the region.

Monday wasn't the best day for dog walking, but it wasn't the worst, either. The skies were gray, there were bouts of light drizzle and temperatures were in the mid-30s.

"This is so much better!" Mr. Carlson said enthusiastically, while equally enthusiastic Callie pranced at the end of her leash. "The past few weeks were crazy!" with single-digit temperatures, daily snow and icy sidewalks.

Callie, a 1-year-old basset hound, was his first client on Monday. She was clearly happy to see Mr. Carlson and delighted to get some pets and pats from a reporter and a photographer. During her 30-minute outing in Shadyside, she walked, sniffed and did her business.

Callie looked sad when Mr. Carlson took her back to her house.

"Come on, Callie, I'll get you a treat," he said. Callie wagged her tail and bounded up the steps and through the door.

Mr. Carlson and his boss, PetSitPgh owner Denise Lohr of Squirrel Hill, roll with the punches, weatherwise.

"I tell people we're like the post office. We always work," Ms. Lohr said. But when temperatures go below 25 degrees or above 85 degrees, "We just do a very basic pee and poop walk."

She has owned her business for five years and works with seven independent contractors, including Mr. Carlson. She has about 120 clients in Squirrel Hill, Shadyside, Greenfield and the South Side.

Dogs like Callie get midday walks while their owners are at work. But PetSitPgh also makes one to three visits a day to care for dogs, cats, turtles, gerbils, rats and fish whose owners are on vacation or business trips.

Some dogs don't like the cold. Others don't like rain. Mr. Carlson doesn't make them walk for 30 minutes if they balk.

Many dogs suit up for the elements. "Some have sweaters or coats, and a Chihuahua wears a hoodie," he said. One even wears boots.

Next up on Monday was Gracie, a black mixed-breed dog adopted from the Western Pennsylvania Humane Society. She's Miss July in the shelter's 2010 calendar, Mr. Carlson pointed out.

As Gracie wagged her tail through Shadyside, Mr. Carlson noted that pet-sitter clients are generally walked one at a time, except for households that have multiple dogs.

After Gracie, he drove to the South Side where five dogs were waiting, and then to Greenfield where he walked three dogs.

"I've always loved dogs, and I started dog walking in college when I needed a part-time job," he said.

After graduating from the University of Pittsburgh in 2008, where he majored in political science and history, he landed a "real" job "but got laid off because of the economy." So for now he walks dogs midday and works in a bar at night, and that's OK for now.

Mr. Carlson generally works three to five hours daily, Monday through Friday. Most walks are about a mile, "but some dogs walk slower than others."

The fee for each midday walk is $18, the same charge for each home visit when owners are out of town. The charge is $15 for "potty breaks with poop scoop in your yard."

Ms. Lohr is bonded and insured. Go to petsitpgh.com for more information.

Pet sitters and dog walkers generally serve clients in a geographic area that is close to home. Ms. Lohr meets regularly with members of Southwestern PA Pet Sitters Network, who refer clients to sitters in their area.

The competition is being billed as a kind of canine olympics. Events include dog diving, agility, weave pole racing, freestyle flying disc and Jack Russell hurdle racing.

The official name is The Purina Incredible Dog Challenge National Championships. It will be televised nationally tomorrow 4-5 p.m. on ABC.

Here's another Olympic tie-in: Greg Louganis, the gold-medal- winning U.S. diver from the 1980s, is competing in agility with his dog, Doby.