Jowsey (17), the head boy at Kaikorai Valley College, was third two years ago, second last year and the winner this year in a time of 35.50sec.
Clubmate John Gilmour was second in 36.10sec and Robert Jopp (Hill City) third in 36.90sec.
The women's winner was Oamaru schoolgirl Megan McPhail (Hill City), who was competing in the event for the first time.
She won in 39.40sec from 2008 winner Fiona Hely (Hill City, 40.20sec) and Rebekah Greene (Hill City, 41sec).
This was the 20th year the street race had been held over the tough 243m course.
The race starts when the Dunedin Town Hall clock strikes the first of its 10 strokes at 10am, with the aim being to reach the finish before the clock strikes 10.
Steady rain made the ground slippery and it was impossible to beat the clock this year.
Jowsey knew the course and was clear about the tactics he wanted to use.
"I wanted to get on the inside and be the first to the top of the hill," he said.
He was first to the top of the hill beside the Robbie Burns statue and was able to get the inside running down to the Regent Theatre and control the race.
Jowsey kept his footing as he hurtled down the slippery slope and had a 5m lead over Gilmour as they passed the Regent Theatre and headed for home.
He was confident at this stage but knew he still had some hard work to do.
"It is almost like a 400m race in terms of the heaviness in the muscles after the downhill," Jowsey said.
"It was a tough last 50m up the hill to the finish."
McPhail was the surprise packet in the women's race because she beat two previous winners and Greene, the most promising female middle-distance runner in the country.
But it is a sprint race and McPhail knew she had the speed to win after finishing third in the senior girls 100m and fourth in the 200m at the New Zealand secondary schools championships in Hastings in December.
She has a personal best 200m of 25.39sec and knew that she would just have to hold on a bit longer to collect the $300 first prize that is given to the men's and women's winners.
McPhail (16), a pupil at Waitaki Girls' High School, left Oamaru at 7.30am to get to Dunedin in time for the race.
"I wanted to get to the top of the hill first and go fast down the other side,"she said.
She had a 3m lead over Fiona Hely and Greene at the top of the hill and increased it to 4m down the hill.
But she knew that the more experienced runners would attempt to run her down over the last 50m.
"The last 50m was hard and I had to push myself," McPhail said.
